An operating system is like a boss that tells all the other programs in a computer what to do. It's a really big and important job, so sometimes people like to make their own operating systems as a fun project.
Think of it like building a toy house out of Legos. You get to choose what rooms and furniture it has, and how it all fits together. With an operating system project, you get to choose what programs it runs and how they all work together.
But just like building a Lego house, making an operating system project can be really complicated. You have to know a lot about how computers and programs work to make it work right.
Some people like to make their own operating systems just for fun, but others might do it as a job. Companies might make their own operating systems to use in their products, like a car company building an operating system for their car's computer.
So, making an operating system project is like building a big toy for your computer, but it can also be a really important job for companies and technology experts.