Okay kiddo, let me explain to you what mkisofs is.
Have you ever burned a CD or a DVD? Well, before you do that, you need to create what is called an ISO image. An ISO image is like a copy of all the files and folders that you want to put on the CD or DVD.
mkisofs is a tool that helps you create this ISO image. It takes all the files and folders that you want to put on the CD or DVD and turns them into a single file that can be burned onto the disc.
If you want to make a CD or DVD that has music, videos or pictures, you can use mkisofs to create an ISO image of all these files. Then, you can use a burning software to burn the ISO image onto a CD or DVD.
So, to sum it up, mkisofs helps you create a single file that contains all the files and folders you want to burn onto a CD or DVD.