I assume you removed it from the slide. Turn it so the bushing is facing up with the sides facing the outter edges of the slide. That is where the two cutouts slots are located. Push the bushing into the cut out slots. It will snap in. Then tip the bushing down and you will be done.It may take a bit of wiggling but it gets easier each time. If you can't get the barrel into the bushing that takes some lube and a good alignment of the parts. Bruce