iPad problem with overweight GarageBand GarageBand occupies 13 gigs, but the app itself is only a couple hundred megs. How can I delete whatever files, etc are bulking it up?
Go to Settings > General > Useage at the Top you should get a list of all the Apps (may take a few to a few more Minutes)

Now Locate GarageBand and delete what you don't need anymore.

Maybe there is nothing listed then just delete GarageBand and reinstall it.