Proper installation of the belt is very important, failure to follow the instructions can lead to damage of the belt

The CoreXY belt is provided in one continuous length. Unroll the belt and cut it in half to give you two belts of the same length

Position one half of the belt so that the toothed side faces the frame, and the smooth side faces the bearing stacks

Slot this half to the bottom of the CoreXY motor assembly, it should align with the bottom bearing stack

Take the other half of the CoreXY belt. Again, position the belt so that the toothed side faces the frame and the smooth side faces the bearing stacks

Form a loop as shown, this will be used to engage with the NEMA17 motor pulley

Position the upper belt as shown

Make sure that both belts match the third image before proceeding