scroll lock plugin?

I’m not sure if that’s what it is, but i’m looking for a plugin that will let me freeze part of the screens so as a user scrolls down the section will change until it ends what i’ve programmed it to do (scroll left/right, add photos etc) and then the site will continue to scroll to the bottom.

https://www.ringly.com has a good example where the phone sticks there until you scroll far enough..

Thanks guys!