Claps are just a way to show appreciation to a post. It really doesn't do or mean anything. It's one of Medium's vanity metrics. It feels great to have lots of claps, but there's no monetary benefit to it. There used to be a monetary benefit to clapping and some writers are still stuck in that mindset so tell new writers that they need to focus on clapping and getting loads of them. But it doesn't matter anyway.
1 clap is the lowest you can give and 50 claps is the highest. Loads of readers and writers classify the claps in different ways, so it's hard to decipher what a reader means when they give you 22 claps over 30 claps.