In order for the cross-slide to slide smoothly and wobble-free on the gantry main beam, you must first adjust the eccentric spacers of the bottom three V-wheels. Adjust the eccentric spacers using the eccentric spacer adjustment reference guide.
Once you have adjusted the spacers, slide the cross-slide onto the gantry main beam.
Use a belt clip, M5 x 10mm screw, and M5 tee nut to secure one end of the 2m long GT2 timing belt to the end of the gantry main beam. The belt must be wrapped through the clip as outlined in the Belt Clip Installation reference guide.
Feed the end of the GT2 belt under the end V-wheel of your cross-slide, then over the motor pulley and under the remaining three V-Wheels. The flat side of the belt should be in contact with your V-wheels while the toothed side should engage with the teeth on the pulley.
Make sure that the belt is not twisted anywhere.
Secure the belt at the other end of the gantry with another belt clip, M5 x 10mm screw, and M5 tee nut. Put a small amount of tension on the belt as you tighten the M5 screw.