Great tutorial on how to achieve a proper leg drive.
This is to indicate all paddlers need to get ready to leave the docks, and should position their hips as close to the side of the boat as possible.
Raise your paddle to a position that is ready to paddle, 2-3" above the water.
Start paddling in synch with row 1.
Raise your paddle over the water in reverse direction, prepare to paddle backwards.
Begin back paddling in synch with row 1.
Stop paddling and let your paddle rest across your lap and the gunnel.
Rest your paddle blade flat on top of the water to act as a stabilizer when a wave is coming at your boat, or two paddlers need to switch positions in the boat.
Indicates the boat is ready to do a race piece start, usually heard prior to start commands at the start line, also during practicing starts.
Check out this great video