Originally Posted by BendtheBar
I like to move my feet just right in front of the bench/box. Some guys move the bench all the way in but it will force a wider stance and awkward squat unless the bench is low.
Squat normally until your butt feels the box. Then sit without rounding your back, but only long enough to feel like you've placed your weight on the box.
I would start with 40% of your 1RM to get a feel for the lift and add weight each set as you feel comfortable. Initially 80% of my 1RM was tough. Now 90% is easy.
Some make use of the box with one of the corners facing forwards which means it won't interfere with a narrower squat stance.