Question How do I set up a 2nd router to share internet but create it's on Wifi SSD

[eyespider]

Hi I've got a zyxel router in this building and it gives me and otheres internet via ethernet and wifi.
There's a room at the end of the building that there was another router in that was connected to the zyxel router by a long ethernet cable. This router has its own wifi network.
However the 2nd router recently stopped working. I got a replacement but if I plug it in the wifi in the main building runs very poor.
How can I configure it not to throttle everyones wifi?
thanks

 

[Alabalcho]

Probably you've connected the second router thhru the WAN port.
Disable that second router' DHCP server, assign it an IP address from main router' IP range, and connect the cable from the main router to one of the LAN ports.

 

[eyespider]

Hi i didn't plug it into the WAN port I plugged it into one of the others.
However I didn't know I have to give it a static IP from the main zyxel router so thanks