Instructions for Transmission:

1. From Menu select File > Create new Torrent (or CTRL + N)

2. Select the files and or directories

3. Trackers: This is probably the hard part for most people. But it’s pretty easy, just put in one of the popular public trackers. we can use one or more trackers, but in generally one/two  is/are enough.

Here are some good trackers to use:

http://open.tracker.thepiratebay.se/announce

http://www.torrent-downloads.to:2710/announce

http://denis.stalker.h3q.com:6969/announce

http://tracker.openbittorrent.com/announce

http://www.torrent-downloads.to:2710/announce

http://tracker.prq.to/announce

http://tpb.tracker.prq.to/announce

http://www.the-underdogs.info:6969/announce

http://tracker.ydy.com:83/announce

http://bt.btbbt.com:7272/announce

http://tracker1.torrentum.pl:6969/announce

http://www.sumotracker.com/announce

Paste one or more of above links in the tracker box. The empty lines in between above links are intentional.

4. Do NOT tick the private torrent box (unless you’re using a private tracker)

5. Save the torrent and send it to friends besides uploading it to one or more sites.

The above entries of Trackers can also be pasted in an existing download via its property box to speed up a download. As for creating public torrent they do not accept upload from public. One has to register with one of the sites and upload the torrent. A registered user can upload torrent anonymously as well.
All the best.