You need 2 M2 bolts (skirted to be flush) and 2 M2 metal threaded inserts (see the picture).

I printed these models on their sides using a Core ONE. This helps the appearance of the slider top. Note that you will need to set the slider STL standing up on the side with the thick part when printing.

Note: The two sliders are identical, however, the clips are distinct on the left and on the right. It can be a bit tricky to attach the bolt. I found taping the slider and clip in place helped with some temporary masking tape.