Separate the two rubber components of the round violin mute by pulling on the top and bottom of the mute.
Find the top part of the mute that has a small ledge a few centimeters wide and a flap that is designed to fit over the bridge. The ledge rests on top of the bridge. There are two round holes toward the middle of the mute. Slide the mute over the center two D and A strings, between the tailpiece and the bridge with the flap on the side of the bridge facing the violin neck. The other side of the mute should face the tailpiece.
Reconnect the bottom part of the mute by pressing it into the grips from the top part of the violin mute. These parts should slide together easily; if they don't, turn the bottom part around since you have put the bottom part on backwards. The bottom part of the mute goes on the side of the bridge closest to the tailpiece.