The creator of that thing, @mSparks is around here. When he is not busy finding flaws in the new MSFS2020, he can probably tell you everything you wanna know.
As any feedback is appreciated, here is mine:
I tried to find out what that software actually does and did not really succeed. I think it is kind of a speech to text interface to X-Plane ATC. If you want to learn ATC, there are plenty resources on phraseology on the web and Youtube. You can even listen into actual ATC at https://www.liveatc.net/ and pick up things.
Unfortunately those automated ATCs are not really immersive nor are they realistic.
If you have a basic understanding (how to do requests and handle instructions), just hop on IVAO or VATSIM. Put a info in your flightplan that you are new and ATC will be forgiving (as they usually are). Some Youtubers (like V1, the real Airbus pilot) are really crazy about PilotEdge. I didn't really look into it, but it seems it is quite professional, with real world ATC controllers practising there.