Replying to STH16 Forward Pressure Adjustment

Got new boots, need to adjust my forward pressure. These are the only bindings I have never dealt with until I got them on my LL2s last year. Shop guy I talked to said to click the boot in, and the worm screw will be flush with the back of the binding track. Got home, adjusted them, clicked my boots in and....The worm screw does not move. It is fixed, the heel piece floats over it and move back and forth when it is adjusted. So either the shop guy is wrong, or I'm blind. Maybe both. Anyways, how are these adjusted? I see an arrow on the side of the heel track but I don't know if that's relevant or supposed to line up with anything. The worm screw definitely does not move. No one will held liable for telling me how to adjust it, I'm not a tool. Same thing the shop guy said, and I told him no worries. I would just like to know when it is "properly adjusted".

Much thanks for any legitimate help.