New wireless printer is typically equipped with WPS button, push this button and at the same time login to the router to activate the WPS function, the pairing process typically lasts 2 min. repeat the process if fails first time
Or read printer manual.
The best way to configure your second router is
1. change the IP adress range from 1 to let's say 200 (192.168.1.1 - 192.168.1.200)
2. set the second router to AP mode (Access point)
3. Disable DHCP in the second router
4. Use fixed IP address for the second router, the IP address should be outside of main route IP range, e.g., 192.168.1.210
5. connect two routers, DO NOT USE internet port!
I typically use the same SSID for both routers.