Can you put mission objectives in a GMod game?

hi, i was wondering if it is possible to make a mission objective for a game, like with a tool or something like that, or if it is possible in the hammer editor, with a trigger or something,something that shows up in the hud when you do something, or maybe in a screen, that would also be usefull.

I’m sure there’s an addon for that, but in vanilla Gmod, there’s no such tool.