After you get through the first tutorials of Last Oasis and have learned how to make weapons, water, and your first Walker, you will be tasked with the Survival of the Fittest mission. This is pretty much being thrown in at the deep end, as you go from the tutorial to trying to do something that involves a lot of combat, travel, and getting hit by monkeys.
For the Survival of the Fittest mission, you need to kill ten Rupus and loot five Rupu Urns. Killing the Rupus is quite easy, and won’t be a problem. Surviving long enough to find five Rupu Urns can be a more significant issue.
The first thing you need to do is to find Rupu camps. If you open your map using the M button, you will see red exclamation points on the map.
These are Rupu Camps, but they are quite dangerous, especially if you are on your own. Head for one the camps, then look for tall buildings on stilts. These strange huts are where the Rupus keep their urns.
You can use your grappling hook to climb up to the roof so you can get in and loot the urns, but there will probably be a lot of Rupus around, and some of them can be quite dangerous.
There is also another issue because these urns are a hot item for players, and there is a good chance it will already have been looted. They take quite a while to spawn back in, so if you are struggling to find them on your server, it can be a good idea to head to the edge of the map and try a different one.
You’ll need your Walker, lots of water, some weapons, and lots of bandages for this quest. Travel to the camp, then find the huts. Try to take out as many Rupus as you can in solo combat unless you have some friends with you. Grapple to the roof, then jump in the hole you will find there and loot the urn.
Make sure you take the time to heal up between fights, and always grab resources to make more water, bandages, and even a new weapon if the one you have breaks.
Survival of the Fittest is the kind of mission you should probably do in the background while you explore your server and find other loot and resources that you need to progress in the game.