Left and right arrows to move through the slides. To have Scratch Cat speak, click on him.
In this project, you can learn about custom blocks, how to make them, their uses, when to use them, and their differences from repeat loops. This only teaches the basics, so if you're searching for a better understanding of custom blocks with strings, Booleans, etc. attached, then head on over to the wiki: https://wiki.scratch.mit.edu/wiki/Custom_Blocks This article touches on Booleans and the like in Custom Blocks. This was made entirely by me, except: I got the music, "Fluffing A Duck" by Kevin MacLeod, from this project: https://scratch.mit.edu/projects/25786440/