I bought Stack Master for my Iphone. Seems to be a great tool for getting better at my stack but there are a lot of options I don't understand and I don't see any help file.

I have low visions so maybe it's there and I missed it.

Can anyone help me find the help file or just answer some questions for me?

Such as:

What are?
Best Cards
Worst Cards
Progressive Mix
Spelling Indexes
Negative Indexes