http://www.bittorrentguide.co.uk/howtoseedutorrent.html will tell you all you need to know :-)

Just add water and add sunlight. Don't forget to get the right potting soil too.

To begin seeding your torrent, you will need to open it in your default BitTorrent client. Torrent files can be opened in basically two different ways. Open a Torrent File Locally - Using this method, you would use a file explorer such as My Computer or Windows Explorer to locate (on your harddrive) the torrent that you created and double-click it. It should then open in your default BitTorrent client and ask your for a Save Location. Use your internet browser to open the torrent in your bittorent client (eg. Utorrent) - Using this method, you would click a hypertext link to the online location of the torrent file. If your web browser is configured properly, it should ask you if you want to Save or Open the torrent file when you click the link. By choosing Open, it should download the torrent file to a temporary folder, open it in your default BitTorrent client and prompt you for a Save Location. Once you are uploading the torrent, you become a leecher. Your Bittorrent client will show you how much of the torrent is uploaded/downloaded. Obviously, your downloads will complete first, and then if you wish you could keep uploading the rest of the file. Once the upload is complete, you become a 'seeder', so other people can download from you. The more seeders, the better for other people. P2P is all about sharing =D

after it finishes downloading, keep it to upload.

You dont have to seed it as it automatically seeds if you like to create torrent files then read this http://tutorial-net.blogspot.com/2009/03/how-to-create-torrent-and-publicize-for.html this has the steps form creating torrent to seeding