Motor brake by means of a shift paddle?

Hello everyone. I’ve had a Si4 for a few days. I’ve been on the road with a Mercedes CLK for a long time, which I’ve only given me a wistfully. I’m all the more grateful that the Evoque meets my expectations so much. I had planned to drive more quietly, and in fact the new car gives me a pleasant calmness. Unfortunately, there’s no hand-operated petrol engine; I had my hope set on the switch-buttons, but it doesn’t seem to get into lower gears really quickly, for example, to brake with the engine. I’d like to understand what the car is doing when I pull on the left paddle; there seems to be something like a short idle moment before the new gear grabs. Can anyone explain that to me?