It takes practice. Please practice with an old tip that no one cares about.

Only loosen the middle screw. Do not take out the screw completely (it is easy to loose). Be gentle with the screw. It is a standard right-handed screw (clockwise will tighten). Don't over tighten. It should be just tight enough so the tip doesn't fall out. When loosening/tightening, make sure the Phillips screw driver is fully seated in the head of the screw to avoid striping the head.

The images below show a tip that is pushed too far underneath the clamp, and a tip that isn't pushed far enough under the clamp. In these configurations, it took a drive amplitude of 300 mV to get the tip to oscillate. The tip oscillations were not stable (the amplitude drifted up and down).

The image below shows a tip that is loaded well. When this tip was tuned, the drive amplitude was less than 100 mV. The amplitude was more stable.

The image below shows a tip that is mounted correctly. The purple line (aligned with the tip) is parallel with the blue line (aligned with glass window).