How to set up communication between router and cisco switch?

Question

network hardware

Previously, I never set up cisco, but they suddenly instructed me to disassemble and configure it. The situation is this: there is a c3750x router (its config is presented below, it is the core of the network, it has several vlays), an sg 300-52 switch was connected to it, on which there was pppoe and the Internet came from here. The login and password for this switch was lost and reset, now you need to reconfigure it. Therefore, I ask knowledgeable people to suggest first what settings are needed on the switch so that it can at least become visible from the main network.

!
! Last configuration change at 11:29:55 YKT Thu Mar 31 2011 by admin
! NVRAM config last updated at 11:30:03 YKT Thu Mar 31 2011 by admin
!
version 15.0
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec localtime show-timezone
no service password-encryption
!
hostname gz-core
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$KKXH$uHZKm4gL6NqVerKDMZsaY/
!
username admin privilege 15 password 0 12#$qwER
aaa new-model
!
!
aaa authentication login default local-case
aaa authorization exec default local if-authenticated 
!
!
!
!
!
!
aaa session-id common
clock timezone YKT 5 0
switch 1 provision ws-c3750x-24
system mtu routing 1500
ip routing
!
!
ip domain-name meridian.local
ip name-server 10.40.3.2
ip name-server 10.44.3.2
login block-for 300 attempts 4 within 120
login delay 2
login on-failure log
login on-success log
vtp mode transparent
!
!
crypto pki trustpoint TP-self-signed-3463912960
 enrollment selfsigned
 subject-name cn=IOS-Self-Signed-Certificate-3463912960
 revocation-check none
 rsakeypair TP-self-signed-3463912960
!
!
crypto pki certificate chain TP-self-signed-3463912960
 certificate self-signed 04
  3082022B 30820194 A0030201 02020104 300D0609 2A864886 F70D0101 05050030 
  31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274 
  69666963 6174652D 33343633 39313239 3630301E 170D3131 30333330 31333134 
  32315A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649 
  4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D33 34363339 
  31323936 3030819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281 
  8100B630 A4A6E8B0 7886A9FC F247DE38 07A103A8 D5A9DF4A ACD33140 40017FF0 
  8A962D16 F0112B14 A7464D79 00FABAA6 8C9084F2 36FA4799 1D839743 4E149551 
  287E8077 F233D45C 79E28E8B 6C2F3053 6F5F61B2 6EE2DB6C E7DA6246 425C022F 
  29CA9D6B C550B063 3ADD10BE 738F75AE 90222383 32C733BA 77B3E964 1AEA0260 
  12170203 010001A3 53305130 0F060355 1D130101 FF040530 030101FF 301F0603 
  551D2304 18301680 14DF9DED 02787541 4A58DF60 BEFB7AB4 EF8164BA A9301D06 
  03551D0E 04160414 DF9DED02 7875414A 58DF60BE FB7AB4EF 8164BAA9 300D0609 
  2A864886 F70D0101 05050003 8181005D 15F4A184 C03C1591 875C5E6A 74428561 
  0FE33A58 A84E7B51 447FBD2A 2ED7C721 F5E81BFB 9D8D5285 00039BCC 901EE3F6 
  8942C8D4 3FC2036E 8443CFB6 CC42DFB5 C93178F3 A08C6A9B 9FA937BA DCF3679B 
  29AE40FA E2155966 3C4DB116 40502ACC E71F0AB2 692DCB25 7E1A291D 3D44DCC2 
  4D38732B D98D4011 6D7FBFC8 9F4A9A
  	quit
archive
 log config
  hidekeys
 path ftp://cisco:[email protected]/$h
 write-memory
!
!
!
!
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 1 priority 24576
!
!
!
!
!
port-channel load-balance src-dst-ip
!
!
!
!
vlan internal allocation policy ascending
!
vlan 3,41-42,50,66,77-78,90-91,99-100,111,240,300-301,666,999 
!
vlan 2275
 name gz-srv-rt
!
ip ftp source-interface Loopback100
ip tftp source-interface Loopback100
ip ssh version 1
ip scp server enable
!
! 
!
!
!
!
!
!
!
!
interface Loopback100
 ip address 10.40.253.144 255.255.255.255
!
interface Port-channel1
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface Port-channel3
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface Port-channel4
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface Port-channel5
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface Port-channel6
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface Port-channel7
 switchport access vlan 240
 switchport mode access
!
interface Port-channel8
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface FastEthernet0
 no ip address
 no ip route-cache
!
interface GigabitEthernet1/0/1
 switchport access vlan 100
 switchport mode access
!
interface GigabitEthernet1/0/2
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface GigabitEthernet1/0/3
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 1 mode on
!
interface GigabitEthernet1/0/4
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 1 mode on
!
interface GigabitEthernet1/0/5
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 3 mode on
!
interface GigabitEthernet1/0/6
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 3 mode on
!
interface GigabitEthernet1/0/7
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 3 mode on
!
interface GigabitEthernet1/0/8
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 3 mode on
!
interface GigabitEthernet1/0/9
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 4 mode on
!
interface GigabitEthernet1/0/10
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 4 mode on
!
interface GigabitEthernet1/0/11
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 4 mode on
!
interface GigabitEthernet1/0/12
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 4 mode on
!
interface GigabitEthernet1/0/13
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 5 mode on
!
interface GigabitEthernet1/0/14
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 5 mode on
!
interface GigabitEthernet1/0/15
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 6 mode on
!
interface GigabitEthernet1/0/16
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 6 mode on
!
interface GigabitEthernet1/0/17
 switchport access vlan 240
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/18
 switchport access vlan 240
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/19
 switchport trunk encapsulation dot1q
 switchport mode trunk
 spanning-tree portfast
!
interface GigabitEthernet1/0/20
 switchport access vlan 78
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/21
 switchport access vlan 666
 switchport trunk encapsulation dot1q
 switchport mode access
!
interface GigabitEthernet1/0/22
 switchport access vlan 77
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/23
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 8 mode on
!
interface GigabitEthernet1/0/24
 switchport trunk encapsulation dot1q
 switchport mode trunk
 channel-group 8 mode on
!
interface GigabitEthernet1/1/1
!
interface GigabitEthernet1/1/2
!
interface GigabitEthernet1/1/3
!
interface GigabitEthernet1/1/4
!
interface TenGigabitEthernet1/1/1
!
interface TenGigabitEthernet1/1/2
!
interface Vlan1
 no ip address
!
interface Vlan3
 ip address 10.44.3.1 255.255.255.0
!
interface Vlan50
 ip address 10.40.50.1 255.255.255.0
!
interface Vlan52
 no ip address
!
interface Vlan77
 ip address 10.41.0.1 255.255.255.0
!
interface Vlan78
 ip address 10.43.1.1 255.255.255.0
!
interface Vlan90
 ip address 10.44.255.2 255.255.255.252
!
interface Vlan99
 ip address 10.44.0.1 255.255.255.0
 ip helper-address 10.44.3.2
!
interface Vlan100
 ip address 10.44.1.1 255.255.255.0
 ip helper-address 10.44.0.2
!
interface Vlan111
 ip address 10.44.111.1 255.255.255.0
 ip helper-address 10.44.3.2
!
interface Vlan240
 ip address 10.44.240.1 255.255.255.0
 ip helper-address 10.44.3.2
!
interface Vlan2275
 no ip address
!
router ospf 1
 network 10.40.253.144 0.0.0.0 area 0
 network 10.40.0.0 0.0.255.255 area 0
 network 10.44.0.0 0.0.255.255 area 0
!
ip http server
ip http secure-server
!
ip route 0.0.0.0 0.0.0.0 10.44.255.1
ip route 10.40.1.0 255.255.255.0 10.44.1.66
ip route 10.40.2.0 255.255.255.0 10.44.1.66
ip route 10.40.3.0 255.255.255.0 10.44.1.66
ip route 10.40.11.0 255.255.255.0 10.44.1.66
!
ip access-list extended vlan41
 remark GZ_temp<->SRV
 permit ip 172.31.77.0 0.0.0.255 host 10.44.0.188
 permit ip 172.31.77.0 0.0.0.255 host 10.40.1.51
 permit ip 172.31.77.0 0.0.0.255 10.40.40.0 0.0.0.255
 deny   ip 172.31.77.0 0.0.0.255 10.0.0.0 0.255.255.255
 deny   ip 172.31.77.0 0.0.0.255 172.16.0.0 0.15.255.255
 deny   ip 172.31.77.0 0.0.0.255 192.168.0.0 0.0.255.255
 permit ip 172.31.77.0 0.0.0.255 any
!
logging source-interface Loopback100
logging host 10.40.1.62 transport tcp
logging host 10.40.1.62
!
snmp-server community 12#$qwER RO
!
!
!
!
line con 0
line vty 0 4
 logging synchronous
 transport preferred none
 transport input ssh
 escape-character 3
line vty 5 15
!
ntp source Loopback100
ntp server 10.40.3.2
ntp server 10.44.0.2
ntp server 10.40.3.3
ntp server 10.40.1.61 prefer
end

Answer 1

The switch does not particularly need an IP address, except for administration via ssh / telnet, etc.
Then you just need to set the IP to it in the management vlan, like this:

conf t
interface Vlan3
 ip address 10.44.3.100 255.255.255.0
exit
wr

Well, on the interface (port) into which you will stick the wire, like this

switchport trunk encapsulation dot1q
switchport mode trunk

Answer 2

Peploss you are confusing something. sg 300-52 is a switch and it cannot have "pppoe and the Internet came from here"