Sorry, I forgot that Drive doesn't give you a choice on where to download things to... My bad! OK, so Drive saves all documents to your device's Download folder. To move it to Zooper (or to point Zooper to that location, if possible) you need to go to your stock File Manager (in an S6 I believe it's called My Files) and go to the Downloads folder, find the file you're looking for, and long-press on it. That should give you options like moving or copying to another location. Just do that to wherever Zooper needs the files stored.