You get this quest from Dan Hagar, after the prologue where he rescued you from the Bandits and driven you to his base.
Before you do this quest, you should do the Wingstick Mastery quest by talking to Loosum Hagar in the courtyard.
Quell the Bandit Threat is the first real mission you will be doing in the game.
"Talk is cheap in this world, action is needed.
First take the pistol and supplies from the counter. Then grab one of my ATVs and head up north to the ghost hideout.
Don't come back until they are completely wiped out.
You do this for me, and I'll give you some old Ark Armor to fit that Ark suit you are wearing."
Notice the supplies on the desk nearby. Take the items which include the settler pistol, bandages, and a few rounds of ammunition. Then hop on the ATV (Small vehicle) in the garage.
Follow the markers on the radar and drive North to the Ghost Hideout. Its a long, but fun drive, especially if you use the Boost a lot!
Once you get to the hideout, disembark from the ATV, cross the bridge on foot, and head inside the door.
In here your mission is simple, just eliminate any Bandit you find. Make sure to loot any bodies you run across, for cash and ammo.
Go through all the area killing the bandits. Aim for their head to do the most damage.
Make sure to get all the items - There should be a courtyard with beer and a ghost boss collectors card.
Go through some doors, when you get to a room with a big statue the bandits will knock you unconscious and there will be a cutscene. You will have to use the Defibrillator to revive yourself. To use the Defibrillator, press E (on PC) when the two nodes intersect to create a spark and revive yourself. If you dont hit the button in the right time, you will die and have to reload from the last save. Also, depending how close the nodes are when you hit the button, you can get more health.
Keep exploring the area killing any bandits along the way. Take all the ammo you can find. If you happen to run out of ammo, you will have to charge the bandits and punch them to death, immediately looting some more ammo
Eventually you come into a room with some vending machines, look for the rest of the path to the right. Go down the stairs and kill more bandits. Use grenades to clear the room of bandits safely.
Once you've killed all the bandits in the final area, ride the zipline that will take you back to where you started. Exit through the door and ride the ATV back to Dan Hagar to complete the quest and get your reward, a suit of armor.
