Well just pop the old one off with a small flat screwdriver, the new ones can be a bit tricky to install without breaking them. They have 2 things to look at one is a round pin the other is a 1/2 inch long plastic arm. What I do is slip the arm into the slot with the round pin at the at the top then rotate gently clockwise until the pin lines up with its hole, and snap it in. It is very easy to break off the plastic arm portion so be gentle, tho if it does break off it should still work fine as long as the pin portion snaps into place correctly