I'm running a Samsung Tablet Tab 2 10.1 Wifi under Android 4.2.2 and want to go online via a mobile router. While trying to add an APN i did not find the menu "mobile networks". And now?
A router is probably going to give you a wifi signal, so the equivalent of the APN is the router itself. (The APN tells the phone the address of the carrier's internet gateway. A wifi router is the internet gateway.)