How do I add a printer on my iPad3

Hi,

Any information about the printer make and model?

The normal way would be to use an AirPrint-compatible printer model connected to a Wi-Fi router. The iPad would be connected to the same Wi-Fi network.

Use AirPrint to print from your iPhone or iPad - Apple Support

If all Wi-Fi settings are OK, but there is a problem with device discovery, you could try the following power-cycle sequence (with these waiting times; do not forget the router): Power off the Wi-Fi router, the printer, the iPad, and all other connected devices/computers. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the printer. Wait a minute or two. Power on the iPad. Finally, power on all other devices/computers.