In the instruction it says that the z_axis mount 2 pieces should be placed with 16 mm M3 bolds. But 20 mm bolds are needed.
In the kit there is a shrotage of 20 mm bolds.
Sorry but I used the 16mm bolts to mount those pieces.
I thought they were too short too.
As explained in the manual, you should tilt the printer backwards a bit, then the bolt will catch the nut.
I used a magnet to hold the screw in front.
Yes the solution is to turn the printer backwards so that the bolt nut will contact the bolt. I agree maybe 20mm bolt would be better.
Like Raby I used a magnet.
Works very well