@LEGOManiac has is correct.
You use 2x “Blocks of Consistent height”
Turn AC power off on Printer.
PLace one Block under each side of X axis bar to the Base frame of machine.
Grasp the Flexible couplers in each hand.
Manually turn both couplers until X Axis touches both blocks
Remove blocks and Turn AC power back on
V-Slot type:
https://www.thingiverse.com/thing:
Smooth Rod type:
Visual feedback Type:
Prusa Style :