Really hard to help without info.
Is it wireless or wired?
Try googling your model number for info on how to connect to network.
If it was previously connected to a network, should be similar to how it was before.
Most printers come with a Setup Utility, or have a touch panel which allow for you to choose your network and then enter in your network password. Sometimes you'll need a computer to assist.
If the printer is asking for a PIN or a WPS Push, it is recommended not to use these for security reasons. But if you need to use them, the PIN is found either on the side of your router as a number, or you'll find the WPS Push button on the front of the router. Again, highly recommended to not use these - they are best shut off.