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.