On my gun I was unable to remove the Barrel Cam item #28 and the Barrel Cam Bushing item #29. I believe they are press fitted into the frame. With that being said. Insert the left Slide Catch item #30 into the Barrel Cam Bushing. There is a groove in the frame that the Slide Catch Spring item #32 rides in. Place the spring in that groove (if you turn the frame over, you will see the groove) Slide the right Slide Catch item #31 into the Barrel Cam Bushing. From the inside of the slide lift the spring while pushing the right Slide Catch into place. On the inside of the right Slide Catch you will notice a notch that the spring captures. Place the spring over that notch to lock the Slide Catch into place.