Okay kiddo, have you ever watched a video of someone cutting fabric with scissors? Well, using a cutting sequence is like having a plan on how to cut the fabric in the best way possible so you don't waste any of it and it looks nice when you're done.
Think of it like drawing lines on a paper before you cut out a shape. You want to make sure you're cutting in the right places and not wasting any of the paper. The same is true for fabric. You want to cut in a certain order so you don't end up with odd shapes or pieces that are too small.
So a cutting sequence is just a plan for how to cut the fabric in the most efficient and effective way possible. It can take into account things like the width of the fabric, the pattern of the fabric, and how much of it you have. It helps make sure you get the most out of your fabric and avoid any mistakes.