Your printer documentation should tell you how to enter the network SSID and password.
If you want to use WPS, I just press the WPS button on my gateway and use my printer's user interface to search for the WPS signal.
Depending on your router the instructions may be different.
This is the link that I found those instructions in:
But also take not of the warning about using WPS as mentioned in the thread. Much better to scan for your SSID and enter the password as mentioned above.