This footwork is important when your opponent hits a clear shot towards the baseline. You need to stand at a ready position waiting for the feeder to send the shuttle to the baseline.
When the shuttle is hit towards you, ampoule you will need to push out from your ready position with your right leg with your left hand balancing your body.
The shuttle should be hit at the highest point of contact so that you can have more angle to hit the bird. Besides that, sick hitting the shuttle at the highest point of contact will give you more power as well.
Watch how coach Diemo Ruhnow trains his student with this drill so that they can improve their footwork at the rear court.