Animated Scroll in a GUI

Can you please explain more? I don't understand what you mean by "scrolling blocks"

 

Set up a repeating task and change the inventory place every x ticks?

 

You need to have a list of all the items you want to scroll, then set a runnable that runs every x ticks that takes the first item in the list, adds it to the end of the list, then removes it from the start of the list. Then iterate through the items and add them to slots, and finally cancel the initial task.

It's a bit complicated for users who are new to programming, you might want to start with something easier.