Fostech defendar-15 - Fostech Defend AR-15 Complete Assembly Collapsible Stock

Came in a box with no instructions which was frustrating, but I found the info on how to assemble and install on YouTube. Tested it out and could not get the stock to "bump" the trigger even with making adjustments. I know I'm doing something wrong because a lot of people online are rocking these no problem, but I can't seem to get it operating the way I want and I can't find any info from the manufacturer. Thought I'd be able to pop this on my AR and load a 60 round drum and go to town with this thing, but that was not the case.