How do I create a torrent from my video file, and then how do I find my torrent file?

On Transfers view use the +Add button,
go to Create New Seed tab,
use Browse for file... button,
point to the file and click Open,
use Create button,
select newly made torrent task,
go to trackers tab,
right-click on empty space and select Edit Trackers...,
paste tracker url and click OK,
go to Options tab, Meta-Info page, (or right-click torrent > Meta-Info > Save .torrent)
use Save .torrent File button,
point to location and click Save, (preferably some place easy to find, like the desktop).