Basic information:
(Un)surprisingly you won your preliminary. You've been given a slice of the underground near Griffith Park to investigate.
Valeria gets you a general map of the cave system you've been assigned to. However there are some missing areas. Most are small, areas where they aren't sure if recent earthquakes messed things up. Five however are considerably larger.
The most important one is the near surface area. The drow don't go near there, so the entrance is probably monster heavy. Predators trying to get escaped slaves mostly.
The second area is known as the Oubliette. There's a hidden drow outpost near the place, but few people go in there. It's a common hiding place for escaped slaves, but also for escaped XCrawl critters. The passages are difficult to navigate.
The third area is the larva farm. There's an area some demons are using to farm larva. The drow had to abandon their watchpost there, but if you recapture it, they'll move in supplies until you finish your expedition in the area.
The forth and fifth area is beyond the wastes. There's an antimagic zone near the edge of the cave system that popped up fifty years ago. The drow know there are two larger complexes beyond it, but don't know what moved. They have a farm nearby that you can use as an advanced base however.