Check the wiki on Silverwastes for details. The gist is that it is a map that goes through a cycle. First players capture and defend forts, building up their defenses; then players jump into sarlac pits to fight bosses, needing to slay 4 different fort bosses in 15 minutes. After that the choppers land to the west and players go in a multipronged lane attack against another set of bosses, after which if they want they go into a Pac Man maze for phat lewts if they can dodge the one-shot plant wolves.
Meanwhile completing events (which is what moves the map towards the sarlac pit Breach event) rewards things including shovels, which can be used to dig up chests. You buy keys with map-specific currency and if any one person digs up a chest everyone nearby with a key gets to open it. So sometimes people work the events, sometimes they form chest trains to get loot.
After one full cycle from Pact preparation through Vinewrath and Labyrinth, you will have enough loot to need 15 minutes to sort it out.
