how do i make it so that when i double click on a torrent, that i am done downloading in the library, it opens it automatically opens in explorer?
I do not think that is possible. But you can right click -> Content -> show in XXXXX
Where XXXXX is finder if you are on a Mac (which you clearly are not)
and XXXXX is explorer or whatever term is used on Windows
or XXXXX is whatever term is used on the Linux version.
How about Tools->Options->Display->Library - default launch action?