Maybe Im just stupid but......

Maybe Im just stupid but seriously I cant figure it out at all. I payed for this app and I cant even use it. My "thumb" button isnt working, I cant pull up a keyboard and theres some kind of weird lines coming from one side of the page that I cant get rid of! All I wanted was something to draw pictures in for my notes! I payed for this thinking it was good! Not worth it!!!!

Desir d about FastFinga, v2.6.3