When playing in the online mode, the class you have to be in order to obtain this trophy is Engineer.This is achievable right away if you know what you're doing, as I got it in the first match. Simply make your class an Engineer and play the game. If there's an object you can repair, you will see the Wrench/Spanner symbol on the map, go up to where this symbol is, and when you're at the broken object, hold
button on your d-pad to repair it completely. Once done, give the game a minute or two for your trophy to be awarded. You know if you did it successfully as you get points for a "Repair".
Alternatively/more easier, there will be red boxes on the map, this is where the enemy can restore their ammo, go to one of these and shoot at it (Stand back, it explodes), once it's destroyed, you can do as above and just repair it for the trophy.