Assembly note: It's difficult to press the nuts into their receiving recesses on the right-side (short) part. But I found a relatively easy way to do it. Working with the right-side part alone, insert a bolt into the hole in its flange on the part, then reach behind the flange and thread a nut onto the bolt. Tighten down the bolt onto the nut. This will guide the nut into its recess on the flange. Back out the bolt, holding the nut into its recess with your fingertip. Eureka, the nut is securely located in its recess. Proceed with assembly of the 2 parts. (edited)