I'm sure DDAC84 has pointed you in the right direction.
My two penn'orth:
Certainly for your first time do a little preparation.
Make a new folder.
Use your torrent client to create a new torrent. Ignore the box where you need to add the tracker URL. You can put anything in this box. The site software will sort it out later. Save it in your folder.
Grab a cover picture for your movie. Save it in your folder.
Make some thumbnails of your movie (not essential but good). Save in your folder
Find a review of your movie, copy it to a text file and saveโฆ
Do a thorough search of this site to make sure you are not posting a duplicate or your effort will be wasted - different formats and sizes are allowed.
Go to the Upload page -see button at top
Follow the steps for the manual upload, it is fairly logical.
Post your torrent
NOW THE FINAL STEP
If you are successful your torrent will not be visible UNTIL you download the torrent you have just posted and open it as you would any other. Then you must 'save' it to the identical file that you made the torrent from. Your client will then check the file and start seeding. If it does anything else, like downloading, you did not point to the exact same file on your hard disk.
It is really not as hard as it seems. After your first one it is very simple.
I should, of course, add this is only my own guide but a lot of the guides I've seen can look immensely complicated. If things don't go right first time there are people around to help you