It can be raised appropriately, and the router on the roof can be used if conditions permit. Third, don't buy too cheap routers, but don't expect expensive routers to have strong signal penetration. According to my practical experience, your router signal will be better, but it is far less than the transmission speed. If there are many rooms and the area is large, it is necessary to set up an extension route. Be sure to see the wireless fidelity and bandwidth clearly when buying equipment. Don't blindly believe in Gigabit routing. You can choose the bandwidth of the wired port according to the bandwidth of the office.
In addition, if there is a requirement for the transmission speed of the local area network, you need to choose a gigabit wired port. Signal expansion generally adopts wireless relay or wired expansion, which can be selected according to your own network bandwidth requirements. Each floor is equipped with a wireless router, why not use an AP, because an AP is too expensive and saves costs. Set different router addresses to avoid conflicts. The access line is plugged into the router on the first floor, connected to the WAN port, and led from the LAN port to the LAN 1 port of the router on the second floor.
Then lead LAN4 of the router on the second floor to the third floor. And so on. Routers do not use WAN ports. The router does not need to set any internet access mode, only needs to set the name and password of WiFi signal. It is best to have the same name and password, so that you can connect automatically on any floor. Only the router on the first floor is a broadband account configured with PPPOE. The rest of the details are up to you