The pro version adds support for online cloud backup, netplay, and no ads. To use the online cloud backup support, go to settings then Data.

All necessary cores and plugins are included. There are many caveats though.

* There will be issues with specific games or devices.
* Not all games work, but most do.
* For games that do work, you may have to try different video plugins
* Not all video plugins will work with every device, and there could be glitches.
* There are many missing translations. It may be better to stick with English.

The netplay server is only supported in the pro version. To play games over the internet, it requires a router with UPnP and being connected to the router. No UPnP is required to play games locally in the same wifi network.

For support, please go to either: /r/EmulationOnAndroid or www.paulscode.com

Here is a great guide: http://www.paulscode.com/forum/index.php?topic=15692.0
Here is how to modify controller mappings: http://www.paulscode.com/forum/index.php?topic=15812.0