Borderlands 2 My First Gun story mission is activated automatically after the cutscene in Claptrap’s igloo, and its very short and easy, because we only need to get a gun from a cabinet.
In addition to this, while playing Borderlands 2 My First Gun quest we can find the first Vault Symbol in the game, which allows us to receive a Badass Token.
After Handsome Jack left you for dead in Windshear Waste, you escaped the cold and met a CL4P-TP General Purpose Robot the last of his kind on Pandora.
Shortly after you entered Claptrap’s igloo, an enormous bullymong broke in and removed Claptrap’s eye. Claptrap needs your help to get it back. First things first, though: you need a gun. Claptrap has asked you to grab one from his cabinet.
Experience: 71 XP
Borderlands 2 My First Gun is straightforward. After the cutscene where Claptrap’s eye is stolen by a Bullymong, we just need to open the marked cabinet in Claptrap’s igloo in order to acquire our first weapon in the game.
When Borderlands 2 My First Gun starts, we follow Claptrap towards his location.
After he opens the door of his igloo we enter the tunnel and continue to follow the robot, looting every crate we see. When we reach the main chamber, we should see a furnace, and Claptrap stops in front of it.
While facing the said furnace, we turn right and we should see a closed door.
If we open it, we can observe a small room and on a wall a symbol (as seen in the picture below). We investigate the symbol because it is the first Borderlands 2 Vault Symbol which allows us to complete the Cult of the Vault challenge in this area.
Next, we take the pistol from the marked cabinet and complete Borderlands 2 My First Gun, triggering the next one, called Blindsided.