Are you talking about just the trigger itself? If so, just knock out the pin. Pull the front down first. Make sure the hammer is not cocked. Reverse order when putting it back.
If you are talking about the whole mechanism, then it will require a little more work. The hardest part is replacing the main spring and guide, due to the sleeve that is around it, that pushes the ejector cocking rod forward, to catch and set the ejector, when opening the breech.
Bulge, you must have found a new gold trigger. The trigger itself will be easy to replace but installing the mainspring is a little difficult it you aren't mechanically creative. Don't remove the trigger housing without first cocking the hammer. Pulling the trigger with the housing removed will launch the mainspring into your eye. Hold a rag over it.