I tried both this
function newPlayer(player)
local ff = Instance.new("ForceField")
ff.Parent = player.Character
end
game.Players.PlayerAdded:connect(newPlayer)
and
function newPlayer(player)
local ff = Instance.new("ForceField", player.Character)
end
game.Players.PlayerAdded:connect(newPlayer)
but they both didn't work.

2 comments
Please go back here. I edited the script: https://scriptinghelpers.org/questions/15129/this-doesnt-work
Also, if no one answers your question please don't post multiple of the same question.