u/Aeroposis

I just bought the game today and I've been trying to learn how it works. I've been doing alright figuring things out, But I'm stuck on adding U.I. To be more specific, I'm trying to make a platformer where you have to complete it in a certain amount of time. I want to add a countdown on the Hud, but I can't for the life of me figure it out.

I would appreciate if someone could help me out on this.