Simply complete 5 missions started in Fyrestone (Arid Badlands). You can easily earn this just by playing out the main storyline. However, below is a complete list of all Arid Badlands' missions that you can choose from:
Fresh Off The Bus - Guardian Angle
The Doctor Is In - Dr. Zed
Skags At The Gate - Dr. Zed
Claptrap Rescue -Claptrap
Fix’er Upper - Dr. Zed
Blinding Nine-Toes - Dr. Zed
Nine-Toes: Meet T.K Baha - Dr. Zed
Nine-Toes: T.K’s Food - T.K. Baha
Got Grenades? - T.K. Baha
Nine-Toes: Take Him Down - T.K. Baha
Nine-Toes: Time To Collect - T.K. Baha
Job Hunting - Dr. Zed
Sledge: Meet Shep - Dr. Zed
Catch-A-Ride
Bone Head’s Theft
The Piss Wash Hurdle
Return to Zed
Sledge: The Mine Key
Sledge: To The Safe House
Sledge: Battle For The Badlands
Claptrap Rescue: Sledges's Safe House
Side Missions – Shep Sanders
Get The Flock Outa Here
Breaking Wind
What Hit The Fan?
T.K Has More Work
T.K’S Life & Limb
By The Seeds Of Your Pants
Circle Of Death: Meat & Greet (see Circle of Death)
Why Are They Here?
Get A Little Blood On The Tyres
Hidden Journal: The Arid Badlands
Shock: Crystal Harvest
Claptrap rescue Lost Cave
Scavenger: Sniper Rifle
Scavenger: Combat Rifle
The Legend Of Moe & Marley
Find Bruce McClane
Product Recall
Insult To Injury
Scheming Sabotage
Circle Of Death: Round 1
Circle Of Death: Round 2
Circle Of Death: Final Round
Happy Hunting :)