I didn't install it a shop did so I cant tell you how they did it.
But if say a kid just pulls the trigger or a bad guy pulls the trigger while you are wrestling or something the Glock will not fire. You have to have the firearm in your hand while applying pressure to the trigger and while squeezing for it to fire.
You do not have to apply any real extra hard effort for it to fire, just a bit more than your basic shooting grip/motion. So you do not really have to think about it. However you cant limp wrist it or as stated just by pulling the trigger it will not fire.
I also save my thumb knuckle and or hand webbing with the beaver tail like curve at the top.