Have you determined if the slide is off center while its closed as well as opened?
There will be two different procedures if 1-its centered closed and not centered when opened and 2-not centered when either closed or opened. They are both very simple adjustments. If you are having trouble with the slide after viewing the youtube or Lippert videos, PM me and I'll try to help.
Mule: 2016 RAM Mega Cab Dually, 4X4, Demco Hijacker 21K Autoslide on RAM Puck, Laramie, 6.7, Aisin, 4:10's, Loaded
Wagon: 2015 Pinnacle 38FLSA, Sailun G's, Center Point Air Suspension, 572 Watts Solar w/4 T-145s.