I do not see any functionality for auto-starting torrents under Transfers/Meta Info
I am not sure what you are looking for but if you are wanting to auto-load a torrent from a webpage link for example, that would be the function of the browser i.e. with firefox setting Tools/Options/Applications/Torrent files to "Use Tixati"
Then on Tixati, Settings/Transfers/General/Auto Start - Stop/ Start new transfers