What parts does a design system have, how to support development? some documentation with step by step examples uu [on hold]

I'm just starting in the world of ux, I would like to know what a design system has I have read but I still don't understand, the only thing I have been able to do is create some components in figma and choose the letter size and message tables but nothing more, I don't know how to make the grid , so: c I would like to know about the experience of those who have built a design system I want to be able to help the front end. thanks in advance :)