Installing dlc in stem (The Amazing Spider-Man)

Got the key to the game and the dlc can be purchased. How to put dlc without breaking the steam support. When you insert the pandora crack or SKIDROW. Breaks getting the achievements and work of the stem Windows in the game. In a simple transfer of dic to the folder Date the game download the dlc again. Offline generally otkazyvaetsya to run a simple transfer dlc. How to be?