I need help randomly teaming players?

If you want to split the teams evenly, and randomly each time, you can do the following:

local Teams = game:GetService("Teams")
local redTeam = Teams.Red
local blueTeam = Teams.Blue

-- Function to shuffle a table, found here: https://gist.github.com/Uradamus/10323382
local function Shuffle(tbl)
	for i = #tbl, 2, -1 do
		local j = math.random(i)
		tbl[i], tbl[j] = tbl[j], tbl[i]
	end
	return tbl
end

local players = game.Players:GetPlayers()
players = Shuffle(players)

for i = 1, #players do
	local player = players[i]
	
	-- Set every odd number to the blue team, even to red
	local team = i % 2 == 0 and redTeam or blueTeam

	player.Team = team
	player.TeamColor = team.TeamColor
end

If you want the split to be the same every time you can remove the shuffle.