If I have not yet bored you enough with my long series of videos on repairing a Canon SX520 HS Compact Camera, here is one on how to reassemble the afocal part of the lens: the one responsible for changing the focal distance but not capable of providing focus (this is the job of the focusing lens that is attached to the structure that holds the sensor).
The afocal lens also holds the diaphragm, the shutter and the image stabilization lens.
Disassembling these lenses do not automatically give you a clue on how to put them back together. It is a true exercise in solving 3D puzzles like Rubik's cubes.
But once you understand how they operate you will find that other lenses are just variations on the same theme.