Because people who can't step on sewing machines need someone to teach and learn when they come to the company, and the company needs to spend money to teach.

If it's an electric sewing machine, practice empty treading first and master the operation of the sewing machine first. After mastering it, you can thread and practice sewing. If you want to straighten the thread, you can put down the needle, measure the width of the thread you need from the position of the needle with a ruler, mark it, and then sew it along the edge of the mark.