Whats the difference between a 2 stage trigger and a normal one.

Single stage is, one stage to drop the hammer... When you place your finger on it and apply pressure, the trigger shouldn't move at all, until it "breaks" and the gun fires... Its one short pull to make the hammer drop...

Two stage is, two stages to drop the hammer... First pull starts out with "take-up" (sort of like "trigger creep") until it reaches the second stage, at that point it wants to "stop", then with a little more pull the hammer drops... It actually splits the trigger pull weight between 2 stages instead of one... When you pull through the first stage, you reach the "stop", at that point you know you've reached the second stage, after that, any further movement of the trigger will  cause the "break", and the hammer drops... With a properly tuned 2-stage trigger, the second stage "break" should feel crisp as a glass rod snapping in two...