How to set up vlans on Mikrotik RB951G-2HnD?

Question

Mikrotik

Mikrotik RB951G-2hnd, 3 vlans come, you need to spread them over the ports:
vlan 10 to port 2
vlan 20 to port 3
vlan 30 to port 4
according to the documentation, it is done in a similar way:

Add necessary VLAN interfaces on ethernet interface to make it as a VLAN trunk port
/interface vlan
add interface=ether2 name=eth2-vlan200 vlan-id=200
add interface=ether2 name=eth2-vlan300 vlan-id=300
add interface=ether2 name=eth2-vlan400 vlan-id=400
> Add bridges for each VLAN
/interface bridge
add name=bridge-vlan200
add name=bridge-vlan300
add name=bridge-vlan400
> Add VLAN interfaces to their corresponding bridges and ethernet interfaces where untagged traffic is necessary
/interface bridge port
add bridge=bridge-vlan200 interface=eth2-vlan200
add bridge=bridge-vlan200 interface=ether6
add bridge=bridge-vlan300 interface=eth2-vlan300
add bridge=bridge-vlan300 interface=ether7
add bridge=bridge-vlan400 interface=eth2-vlan400
add bridge=bridge-vlan400 interface=ether8

But when adding vlan interfaces to bridges with physical interfaces, it swears that
the interface has already been added to the bridge (i.e. to the general bridge)
/interface bridge port> add bridge=bridge-vlan200 interface=ether3
failure: device already added as bridge por
If you remove or deactivate the common bridge, the connection with the router disappears, only a reset helps. The
address for the common bridge interface is assigned a separate one and the interface is specified as
lan

Answer 1

add bridge=shared bridge here interface=vlan
not here?
in the interface=ether3 command, you need to add a vlan, and not a physical interface?
or remove the common bridge altogether and make the ports independent

Answer 2

Apparently, you already have Taki Ether3 as part of some kind of bridge.
Let's revisit the logic again. (in my version 4th port trunk 3rd - vlan 10 Untaged)
1) Create a bridge for VLAN:
/interface bridge
add fast-forward=no name=br_vlan_10
2) On the "trunk" interface create a vlan subinterface
/interface vlan
add interface=ether4 name =Eth4_vlan_10 vlan-id=10
3) Add a subinterface to the bridge created in step 1, and the port where it should be untaged
/interface bridge port
add bridge=br_vlan_10 interface=Eth4_vlan_10 trusted=yes
add bridge=br_vlan_10 interface=ether3 trusted=yes
Everything seems to be :)
This is the easiest option, since recently 6.41.2, if I'm not mistaken, they made another option for working with VLANs and bridges. But the old one is still available and working. Watch these 2 videos https://www.youtube.com/watch?v=wq6KVWOFhNI (new version of working with VLAN), https://www.youtube.com/watch?v=Np7rAwvAzq4 (old version)
Attention: Work with VLAN on yours it is better to implement through the Switch chip. (See first video)