I've tried making a script in which where you step on a button, and when you step on it, it changes your team. But I don't know how to do it :/
script.Parent.Touched:connect(function(part)
local player = part.Parent.Name
game.Players.player.TeamColor = Color3.new("New yeller")
end)

2 comments
You should probably check if player isn't nil before setting the TeamColor so that the script doesn't error if there's no player.
TeamColor must be a BrickColor value.