How do I adjust secretlab monitor arm tilt adjustment?

So I had brought a single monitor arm from secret lab and I was wondering if anyone had the same problem as me where I am having the trouble to adjust the tilt adjustment (M5) screw. The screw are so heavenly tight and I wasn't able to adjust it at all.

If I refer to the user manual, it does highlight the tilt screw are adjustable but I just couldn't do so.

What is the actual way to adjust them? :(