Most bedroom slides require that you use an adaptor that would have come with the unit. That adaptor then fits onto a drill that you connect to the slide motor from inside the trailer and manually retract that way. Those adaptors are normally in a drawer in the trailer when you get it, or in a pouch with all your manuals. Could be one of those things that you are wondering what the heck is this.....another example of a poorly done PDI...dealer should have shown you that.
2016 Chevy Silverado 2500 Duramax
2016 Rockwood 8289WS, Diamond Pkg.