Here is a good discussion, with some sceenshots.
https://forum.fudiabetes.org/t/getting-started-with-g6-xdrip/
Basically xDrip is an android app, that does what dexcom app does AND MORE.
It is grass roots, developed by folks on their own time, to provide a tool more helpful functionality to users, parents, etc. It keeps adding new features, without need for fda approval, so is “use at your own risk”. The latest G6 transmitters send the bg value to xDrip on phone. In xDrip, at any time you can create events to show activity, food, etc.
On android phone you download the latest release, set some parameters, set up bluetooth connections, and after sensor warm up you start seeing the bg values.