What settings are needed to install a router inside a working network?

Question

Computer networks

Configuration: The
router receives a static ip from the provider.
Internal network 192.168.0.1 - 192.168.0.200, dynamic routing.
The network has a server 192.168.0.2, another server 192.168.0.3 and 15 working machines connected via an unmanaged switch.
I want to add another router for distributing wi-fi, but when it is connected to the network, it does not distribute the Internet, although it seems to work by itself. Maybe it needs special settings for such a network scheme?

Answer 1

what model of router?

Answer 2

I have dd-wrt on this, I did this ...
Assign IP 192.168.0.253
Disable dhcp
wan - disabled
Wire from lan to the 3rd port.
Works.