Orient the object on it's back ( area with 3 slits on bed) with everything going up.
Didn't see a indicator mount for the X axis bar since some of us don't use the stock setup. Should fit snug on the printer, the hole for indicator is 9.8mm but can expand to accept slightly larger ones, smaller shafts will not work. Printed in PETG but you can use whatever. Supports on the overhang are optional.
If you are getting splitting or breakage when putting it on then increase infill to 40% or more. You also need to mount it overhang side first so angled it to seat then push hole side down till locked.
VERSION 2: Just modified the original to have more chamfers but overall the same
VERSION 3: I shortened the clip part to 13mm vs 15mm so it locks much tighter to the bar. This does require a new angle and more force to snap on. Not sure if PLA would be strong enough.