How do I make a party gui with a player limit?

Okay. So the title might make no literal sense at all but I am going to explain it. What I'm trying to achieve right here is to make like a Gui that has a button you can join in to be teleported to a different game once the max players limit has been reached. If you STILL don't know what I'm talking about, basically I've seen this in multiple games like Camping where you go in a bus to wait until it fills up to the limit and it teleports you to a different game but I want to do this in a Gui. Thank you!

(Also if you're generous enough, I was wondering on how it would fit the players tab when they join that includes their name and a picture like how text in a TextButton adjusts the text to fit in.)