You do not have to add any.
It is oiled from the engine. As soon as you start the engine, oil will flow to the clutch and then drain back to the engine.
When you drain the engine oil, you also should drain the clutch but when you add the new engine oil, you do not need to add it to the clutch. You just need to put enough in the engine to also lubricate the clutch (somewhere about an extra pint, I think)