(Part 2) How could I fix my place player in team script?

You close your if with an end before it can reach the elseif, you dont do that.

i removed the first end because you shouldn't close your if before you reach the end. an elseif is part of the if, therefor it shouldn't be closed at that point.

local redready = true

while true do
wait(1)
    for _,player in pairs(game.Players:GetChildren()) do -- Loop trough all players
        if player.TeamColor == BrickColor.new("Medium stone grey") then
            if redready == true then
                redready = false                
                player.TeamColor = BrickColor.new("Really red")
            --removed end
            elseif redready == false then
                redready = true                     
                player.TeamColor = BrickColor.new("Cyan")
            end -- it should be closed here, since elseif is part of the if.
        end
    end
end

This is use in my game Swords and stuff scripted by me! https://www.roblox.com/games/571957768/ASAS

local function Random()
    local plays = game.Players:GetChildren()
    for i = 1, #plays do
            print(plays[i].Name)
            --Players[i].TeamColor = BrickColor.new()
            if TC == 2 then
                plays[i].TeamColor = BrickColor.new("Bright blue")
                TC = 1
            else
                plays[i].TeamColor = BrickColor.new("Bright red")
                TC = 2
            end
    end
end

that or in your code

local redready = true

while true do -- loop
wait(1) -- waits

  for _,player in pairs(game.Players:GetChildren()) do -- Loop trough all players
    if player.TeamColor == BrickColor.new("Medium stone grey") then
     if redready == true then
                   redready = false                
                   player.TeamColor = BrickColor.new("Really red")
      else
                   redready = true                     
                   player.TeamColor = BrickColor.new("Cyan")
end
end
end
end