Okay kiddo, so have you ever heard someone say "actions speak louder than words"? Well, that's kind of like a perverb, which is a saying that changes the words but still means the same thing.
Just like how you might dress up as a superhero for Halloween, a perverb might dress up a little differently than the original saying. But at the end of the day, they both have the same superpower of teaching a lesson or giving advice.
So, let's pretend the original saying was "the early bird catches the worm". A perverb version of that could be "the sleepy mouse misses the cheese". It's saying something similar, but with different words. Make sense?