Okay, so imagine you're playing with toys and different types of toys make you really good at different things. For example, playing with building blocks might make you really good at building tall towers.
Well, people who work with big computer networks (like the internet) have different toys too, but they're not really toys - they're fancy computers and equipment made by a company called Cisco. And if you learn how to use these Cisco toys really well, you can get a special paper called a "certification" that says you're really good at it.
There are different types of Cisco toys and different levels of certification you can get. For example, there are toys for connecting computers to the internet, and toys for making sure the network is working properly. And there are different levels of certification, from beginner to expert.
So, if you want to work with big computer networks and be really good at it, you can study and practice with these Cisco toys, and when you get really good at it, you can get a certification paper that shows everyone how good you are.