The AP acronym stands for Access Point.  This is a device that your wifi device connects to.  Similar to your home router, your computer connects to the router to connect to other things, like the internet.

The Mobostick AP is an access point.   You would connect your Android phone TO the Mobostick in your wifi settings, similar to when you connect your phone to your wifi router at home.  

See below for the guide for the AP Mobostick -

AP Mobostick Guide

The NON-AP mobostick connects to the wifi router in your home, or on your phone when using your phone's wifi hotspot feature, as described in the below guide -

NON-AP Mobostick Guide