If you go to skills than you will see where you can assign them to the mouse buttons or to the number keys after you've turned on Elective mode.
Went back in the game and I still have no clue what you guys are talking about...oh well,maybe I will figure it out when I have more levels...
Unfortunately elective mode doesn't unlock your entire hotbar allowing you to put skills wherever you would like. This is one of my problems with the current setup. I really want the entire hotbar available from lvl 1.
What elective mode does do, is allow you to assign multiple skills from the same category at the same time. In default mode, you can only assign one primary, one secondary, etc. etc.