Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Mods starting editor for the first time (or second ?)

Options -> Preferences

In here you can change file paths and other such stuff.

I do believe the reason you don't see "Main" is you will also need to extract the main file components.

Here is an excellent guide and will help out.

http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=505777&nt=2&page=1