Can anyone ELI5 to me what sharding is?

So I came across this article while researching on Dapps and this whole thing about sharding is confusing me. I just encountered this term and the article itself and even some articles aren’t really helping me understand what it is exactly. I found this post talking about sharding but being the lazy piece of shit that I am, i didn’t really finish reading it.
How does sharding work and why is it important? Need your help guys. Thank you!