A file allocation table, or FAT, is like a map that tells your computer where all the files on a storage device are. Think of it like a treasure map that leads you to wherever the treasure is hidden.
When you save a file on a storage device like a hard drive or a USB stick, your computer needs to know where to put it so it can find it later. The FAT keeps track of where all the files are stored on the device and how much space they take up.
It works like this: when you save a file, your computer looks at the FAT to find an empty space big enough to store the whole file. Then it writes the file to that space and marks it in the FAT so it knows that space is now taken.
When you open a file, your computer looks at the FAT to find where it's stored and then reads it from that location. And when you delete a file, your computer just marks the space it occupied as "empty" in the FAT so it can be used for other files in the future.
So basically, the FAT is a special kind of map that helps your computer keep track of all the files on a storage device.