Hint: In case you just received your pin pusher, I recommend filing down the pushing tip slightly:

The idea is to increase the tip diameter so you can put less pressure on the rivets surface (less chance of deforming it), while maintaining the same force. Or in easier words, you want to distribute load: P=F/A (pressure=force over area)

The tool's leaflet recommends filing it down 2mm. I have not tried since it seems a bit much. I filed it from a tip diameter of 0.9mm to 1.3mm. Due to its conical shape, you don't want to lose too much pusher tip length in order to be able to still fully push the pins out (!)

Place the nose bridge flush on the tool's tube. Make sure pushing tip, pin and tube are in perfect alignment.

By turning the handle on the pin pusher, slowly push out the pin from top to bottom

Each pin might behave differently. Out of the four rivets (two frames) I removed, one took quite some force and came out with a small "pop". One took hard force and came out with a loud "bang". And two came out smooth as butter.