local cd = script.Parent cd.MouseClick:Connect(function() script.Parent.Parent.BrickColor = BrickColor.new("Red") end
You were pretty close. 2 things: First of all, there is no Red BrickColor. There is stuff like Maroon and Really red. Second of all, you forgot to place a close bracket at the end to close off the connected function.
local cd = script.Parent cd.MouseClick:Connect(function() script.Parent.Parent.BrickColor = BrickColor.new("Really red") end)