1. First you need to generate the torrent file. In Transmission, go to File and choose "Create Torrent File". Select the FOLDER of all the audio files. Then, in the Trackers field, put in the announce URL for the tracker (in this case,
http://tracker.rtsr.net/announce.php). Then click "Create". The .torrent file will be created (probably on your desktop).
2. Now, you need to upload the torrent to the tracker. Go to
http://tracker.rtsr.net/torrents-upload.php Fill out the form, including the .torrent file you just generated.
3. Now, you'll need to re-download the torrent file. There will be a link to do so on the webpage. Double-click the newly downloaded .torrent file to open it in Transmission. In Transmission, point the download location to the FOLDER containing the audio files, and then click "Add". It should now verify the files, and after a few seconds, it will start "Seeding" the files. That is, the progress bar will be solid green. Now, just leave Transmission running. People will be able to download the files from you, so long as you are seeding it.