Can anyone help with some advice on fitting some depo aftermarket xenon headlights to a B7 A4?

I have purchased the headlights, and the bulbs including D1S bulbs for the dipped beam.

These are supposed to be a straight swap that will convert my non xenon A4 into having xenon headlights

My question is regarding a ballast- the aftermarket headlights have a connector which plugs into the D1S bulb- then it looks like the other end of this connector comes out the other side and needs to be connected to a ballast? Is this ballast something I need to purchase? I don't suppose my standard non xenon Audi lights have a standard ballast already I'm supposed to swap over?

Thanks in advance