Freeform App: Where is a Basic User’s Guide?

I have yet to find an actual Freeform guide. I have looked at the video “guide” of videos that folks often have linked to, but they do not comprise a full guide.

Where is something with an index or table of contents I can zip through rather than watching videos in hope of finding relevant information?

Where is something that explains the interface? What are the various select tools and what do they do?

I am still looking for something that will give the basics.

Example, what is the Apple Pencil tool for? When I use it, it seems to make a lasso, nut how do I remove the selected area?

In the pic below, I just want the plant without backgtound.

Thanks!