Handgun version:Stapler is folder down in the way it's susposed to staple papers with,the hand model holds it with the thumb just over the top of the stapler,and the bottem is resting on your index finger (anyone with a staper can try this) to fire,you squeeze your thumb down and magically a handgun bullet fires
LMG version:The stapler is in fully extended,so as to staple something to a wall,and the hand model holds the bottom of it by wrapping all fingers around it,and the top is held like this as well,fireing can be done by squeezeing the metal at the top down,and fireing a staple (This can be done in real life as well,and with a lot of pratice,rather fast.)Reloading can either be a drop,or opening the top and inserting a bunch of staplers into the slot for staples (you need to be pretty fast to do with LMG reloading speed...)
Knife version:Held the same way as the LMG model,except with the non-fireing bottem of it where the top would be held as in the LMG model's case.Basically the guy swings the stapler bottem at the enemy and hit's em with the side.
I know...I suck at descriptions...