How to connect the modem to the line?

Question

Computer networks

Hello! I do not understand this, so I ask for help from experts.
The story is this: there is a certain structure, there is also a modem from which an Internet connection is supplied to each room via a lan cable. Drawing (#1)
Now the essence of the idea. Is it possible to somehow connect a modem that has a wi-fi distribution function to a lan cable in one of the rooms and start distributing the Internet? But the problem is that I don't know any provider and network details.

Answer 1

in your case, it's easier to connect the access point to the cable and distribute the Internet from it

Answer 2

I understand that you need to make one of the modems in bridge mode? Or what? Or is the modem not yours at all and you want to take the Internet from it?

Answer 3

on one of the computers, peep all the settings and configure the access point in the same way.
ps There is a possibility that on the access point it will be necessary to change another mac-address copied from the computer.