How do you make a points, promotion system?

So, I have seen other groups have or made their own rank gui. Like home stores and some cafes, I could say.

Here is a picture of example what I mean.

Picture: https://gyazo.com/b01c24c9e7c32a18f90334f45bf3e40d https://gyazo.com/b01c24c9e7c32a18f90334f45bf3e40d

And there is one that makes you have promotion system where in the game the person get's promotion in the game and after they were promoted and then when they go to the group their rank change. And how do you make it where when they make it to the points like Example: They reach to 100 they get rank into a chef to Head chef. Something like that. I feel like you need a bot for it to rank I think.

Anyways this is not a request question I just really wanna know how did they make that? I know how to make a gui. But I wanna know how they made it. I feel like it like too much script they did.