How do you make a Team Teleport Button, and Assign Teams Script?

Heyy~! So I'm making a RP game and I want to make a teleporter so when like say.... you choose your character by walking up to the morph and making contact with the button, it assigns you to the "Roleplayers" team. After that when you go into the lobby you can find the teleport button that'll teleport you to the rest of the game and the area.

The reason why I need this code is because there is another team.... the "Unselected" team. What this team is it's the team where you haven't selected your character yet. And I want it to be like this team cannot use the teleporter to the world. Because I don't want people to use their roblox avatars for the RP. You know~?

Also the team assigner script. I was hoping to get a script that'll help me assign teams when you choose your character after pressing the button. So "Unselected" becomes "Roleplayers". And when you reset it goes from "Roleplayers" to "Unselected" // "Unselected" to "Unselected".

I hope someone will be able to help me with this I know this is a lot to ask. If you have questions please lmk~!