The drop-feed on your Bernina is a very useful feature. You can use it for darning and freehand embroidery etc.
Just remember when you turn the dial to drop the feed your feed dogs/teeth will drop straight away.
When you turn the dial back for normal feed and to raise the feed dog/teeth nothing will happen until you turn your balance/hand wheel.
Turn your hand balance/hand wheel towards you and your feed dogs/teeth will rise.