Once it says seeding that means your download is completely done. It seeds so that the download can be somewhat faster to other downloaders of that specific torrent because you're not downloading it from the actual site, your downloading it from other users that have that torrent on their computer. So, the more seeders, the faster the download.
So when it is done downloading and it says seeding you can just click the "Close" button at the top right corner or click stop on uTorrent. Your download should be where you set the download place to be in the beginning of downloading the torrent. If you know what I mean. You need to have a .rar file opener to open your file though (Usually) so I think WinRAR is the best to go, just search on google.
Anyway that's what I have to say, hope this helped you.