Sticky image gallery from collection

Hi everyone. I’m trying to create a sticky image gallery bound to a collection of images. I’m very much a novice massively over-reaching my skills, but hopefully one of you knows how to help.

I’m trying to achieve something similar to the link below but I’m running into some problems:
https://www.snogproductions.com/projects/gq-jon-hamm

Thanks for any light that can be shed on this.