Help fixing a model rotating script?

I have a script that is meant to rotate a model (90°) when that model touches a certain part. I'm not sure if I put the script for this in that part or somewhere in the model like the primary part. Can someone please tell me how to fix/where to put this?

Model.PrimaryPart.Touched:Connect(function(hit)
    if hit == Part then
        Model:SetPrimaryPartCFrame(Model.PrimaryPart.CFrame * CFrame.Angles(0, math.rad(angleToRotate), 0))
    end
end)

The primary part load when you connected the touch event. So you'll need to use WaitForChild.

Model:WaitForChild("PrimaryPart").Touched:Connect(function(hit)
	if hit == Part then
		Model:SetPrimaryPartCFrame(Model:WaitForChild("PrimaryPart").CFrame * CFrame.Angles(0, math.rad(angleToRotate), 0))
	end
end)