When i was looking into how the parachute brake worked, it was hard to find a definitive answer in my laymans language, so heres one for idiots like me.
The parachute is packed into a 6" diameter drain pipe approximately 2 foot long, the main chute goes in first then the small drogue chute. The drogue has a strong upholstery coil spring sewn into it. The drogue is held in the tube using 2 straps that are held closed by a small loop through which a pin is inserted. When the pin is pulled, the spring ejects the drogue, and the wind pulls this and draws out the main chute - Bingo, you start slowing down.