Okay kiddo, have you ever played with building blocks and put together a big tower? Well, imagine that the tower represents a web page that you want to show on your computer. Sometimes, you might need help from your friends to build the tower, just like a web page might need help from other parts called "includes".
Now, think about the edge of the tower, which is where you can get an overview of the whole thing. In web terms, "edge" means the part of the internet that is closest to you and your computer. So, an edge side include (ESI) is a special way to build a web page by getting help from other includes that are closer to the edge.
Think of it like your friends giving you blocks that are already assembled and you just have to put them in the right place on the tower. This way, you can build the tower faster and it's easier to make changes if you need to.
So basically, a website can use edge side includes to make their web pages load faster by getting help from other pre-built pieces of the web page that are hosted closer to your computer. This makes everything run smoother and quicker, kind of like building a tower with friends.