There's nothing to it really. The folders are structured by date. You'll find a folder called "15" with zip files in it. You can figure out the most recent zip file and use that.Oh yeah good point Pyure, thanks. Perfect opportunity to go figure out how Aroma backup works I guess.
The zip file will contain simply a copy of your SAVES folder. So you just replace the contents of your saves with the contents of the zip, and victory.