looping section of an imported audio file for rehearsal

Kind of weird how everybody thinks of the word loop as this thing and not some thing that you do.

I have a large audio files sent to me by a songwriter. It has him singing and playing guitar on it.

i’m going to add the bass parts but I need to loop (maybe I should say repeat? )sections to practice them first. I can do this on another app like Anytune but I’ve done this before with GB. In the old days I’ve also done it with logic.. I’m trying to transition now to the iPad for recording and this has been a real stumbling block.