As far as I can tell, there are two distinct "doors" on Crew Dragon that house parachute-related equipment. In the below picture, I've outlined the upper door in yellow and the lower one in green.
From the limited videos I've watched, it appears the yellow door detaches first using three springs located where the three holes are in the image. The drogues then deploy using explosive charges.
What I can't figure out is what happens next. It's clear the green door deploys at the time of main chute deployment, however videos of Crew Dragon descending show the main chutes clearly anchored from the upper door. So where are the mains found, and how does the rest of chute deployment work?