Default LG e980 multiwindow

Hello everyone. I'm sorry if I'm posting this in the wrong place but I'm kinda new here. I have an AT&T LG Optimus G Pro[e-980] and recently flashed the newest CandyKat rom for it. The description for the rom says it has MultiWindow , but I can't figure out how to use it. I've tried holding the back button but guess that isnt ir. Can someone please help? Thanks([/SIZE]