Bonus DLC armor should be in your inventory when you start...but they have lvl requirements before you can wear them.
Steam version came with 3 sets of armor...one for each class.
I ended up wearing the Annihilator set until lvl 28 ( lvl 15 requirement )
It was that good...! Way better then anything I found or could make until end game armor sets.
I don't know if you can buy the DLC armor sets separately from the game.
