Call of Duty: Black Ops II

You now have a Career Record which you can access by hitting the X button at the mission select screen, simply scroll over with LB or RB to challenges, and each story mission has challenges. Complete one of these and by the end of the mission the achievement will pop. I completed one of the challenges at the start of the mission and the achievement didn't pop to the end so it looks like you have to finish the current mission to unlock it.

You Should get this by playing the first mission of the campaign, along with the No Man Left Behind" and "Gun Nut" (if you edited you loadout) achievements.