Release two dividers from each side of the MiX module by pinching the white tabs on top of the Mix module.
Set each divider in a safe place and out of your way.
From the front of the MiX Module, locate the locking buttons, little square buttons on either side of the MiX Module. When depressed in, the top of the MiX Module will be able to slide forward along its rails.
Slide forward and lift the top of the module up (as pictured below).
Locate and remove the hollow circular caps on either side of the module.
Slide the top assembly up (or down) until the desired adjustment hole lines up with the cap hole.
Reinsert the circular caps into the proper cap holes to lock the adjustment in place.
When complete, lower the module top back down and slide it back along the rail until it locks back into place.
Finally, remove the Safety Tabs that are in front of the rail locks. Relocate them in front of the rail locks for the new height setting. These tabs assure that the top assembly stays in place on the rail.