How to use the interface
There is so much that is not obvious (to me), Select a region ; (clear that selection). Copy, then paste in another track,at a specific point in the timeline.
UNDO!! Where is that? If it is the hook-left in the toolbar,…
What are the little handles on a selection region? There is a crossed arrows handle, what is its use?
I found a web version of a user guide for iOS. Is there no eBook/PDFs?
I cannot find the answers to the above questions in it.
Ok, another. I made changes (found the use for the four-arrow tool) and close the file. Or open another, there is no prompt to Save?
When I open it again, it has lost the change.
If I choose Save (hammer button menu) it asks if I want to over write.
I feel like a loser 
Ok, reading the other N-track studio forum posts, I find how to Edit files, references to Volume envelope display, stretching a track (for time/bpm adjustment)
Much of the instructions involve right-click actions (I presume hold, in iPad?) or key-click combinations which are not available on iPad.
setting points? how do I set a point for in/out operations?
lanes? can I do the same ops with re-takes, that create lanes, which can then be merged, or sliced up and joined into a final take?
n-track Drums: I see references to drum kit choices, but do not find so many choices included in the Pro version for iPad. Are they plugins?
I can’t help you at the moment I’m afraid.
Just wanted to thank you for bringing it to my attention that there is an iOS/Android app available 
I had no idea.
If I figure out the answer to any of your questions while playing with it, I’ll let you know!
I am struggling with most of the same things so I won’t be much help. But I will commiserate with you - it sure is maddening to hunt around, find a tutorial on the exact thing you want to know, only to have the lecturer skip right over the most essential point you needed answered. I did learn by accident today what the 2 opposite facing arrows symbol does, and I’ve already forgotten it. Oh well…part of being over 65 I guess. I’ll tell you what would help immensely is being able to enlarge the menus and tiny frikkin icons which are impossibly small on an iPad. Half the time I’m hitting the wrong thing or just guessing what that little blur is supposed to be. Yet you can’t argue with the amazing capabilities of the app - my capabilities not so much 
Good luck.