don't modify the file structure, if the file was in a folder, leave it in that folder, if it was a single file and it wasn't in any folder when you made the torrent file, leave it alone, if it was compressed, don't uncompress it etc.
so when you have your file/folder you want to upload, put it in that folder where your UNFINISHED downloads used to go (check your utorrent settings, if you don't know the folder), then open the torrent file you just downloaded from the tracker, right click on it and select 'Force Re-Check', hashing should start now, after this process is done, your torrent is ready for seeding, of course just in case if it's not a connection problem
if you're the visual type, there are countless tutorials on youtube about how to make and seed a torrent using utorrent properly