I'd investigate how such a thing would be done on real film, and then just replicate it using AE techniques. It's a good self-discovery and learning project for an AE beginner.
When you want to replicate an effect download the video and carefully examine the frames.
I see a projector Lens here and something that looks like what it used to look like when we wrote on the leader with a felt pen going through the gate. There's not magic here, just compositing and layers. The pen marks on the film would be achieved by creating a tall and narrow comp, using the right kind of font and blend modes over a background that looked like dirty film leader, then nesting this tall thin comp in another comp that contained the lens elements. You would use a track matte and some overlays to get the look you want. Blend modes will help, and you would use a track matte to reveal only the frame. Then you would animate the position of the tall thin nested comp and Pre.compose the nested comp and the track matte then apply posterize time to get the frames to flicker.
I'm guessing for this shot you would need at least a pre-comp in a pre-comp as I described to to the film leader effect, an image of a lens with some masking, another image of a lens with blend effects and blurs and masks to get the highlights, an image of the chipped glass, and a couple of layers to give you the reflections. Nothing magic, just layers and basic compositing. The only real trick is in pre-composing the film strip and posterizing time so that the leader portion looks like the leader in a film really would.