How to make a network between computers in the office?

Question

Computer networks

Good day, I’m interested in the question of how to implement a network in the office via Wi-Fi (in the office, laptops, printers work via Wi-Fi, telephones, etc. The office is divided into 3 departments, each department has one router. Is it necessary to provide routers with the Internet)? Is it possible to connect wi-fi routers to the light. That is, the provider gives a cable with the Internet, connects to the switch. 3 routers are connected to a switch. (each router will enter into a separate department). And the Internet should be on 3 routers. Does such a network work? Or advise how best to do it, or links to useful material. Thanks

Answer 1

Plug the cable from the provider into the WiFi router, configure the rest of the routers as signal repeaters (WDS) and go ahead.

Answer 2

From Ronald's answer read and do so. It is better to connect the points in the departments to the center with a cable router. And set them up just to distribute wifi. By disabling DHCP.
But in general - call a one-time sysadmin

Answer 3

Hire a specialist, otherwise you will have to do and learn too much for the sake of too little