I've only driven a MK7 Manual 1.6 Diesel which has this and will explain how it worked for me.
When I came to a stand still for traffic lights or something similar, if I put the car in neutral, and foot off the clutch, usually the stop start would kick in, but you would also get the auto-hold on (you should see a green light on the MFD).
When you then slip the car back in gear, and lift the clutch and accelerate, in will then release the auto hold automatically