Tomb Raider Game of the Year Includes the following DLCs:
 
Tomb of the Lost Adventurer (Single player Challenge Tomb)
Scavenger Scout
Scavenger Executioner
Scavenger Bandit
Fisherman
Silverballer
Agency SPS 12
HX AP-15
JAGD P22G
M590 12ga
STG 58 Elite
Hunter Skin
Aviatrix Skin
Guerilla Skin
Demolition Skin
Sure-shot Skin
Mountaineer Skin
Shanty Town
Caves and Cliffs Multiplayer Map Pack
1939 Multiplayer Map Pack
Shipwrecked Multiplayer Map Pack
 
Tomb Raider details
Tomb Raider is a critically acclaimed action adventure that explores the intense and gritty origin story of Lara Croft and her ascent from a young woman to a hardened survivor. Armed only with raw instincts and the ability to push beyond the limits of human endurance, Lara must fight to unravel the dark history of a forgotten island to escape its relentless hold. The Game of the Year edition includes the Tomb of the Lost Adventurer, 6 single player outfits for Lara, 6 multiplayer weapons, 8 multiplayer maps, and 4 characters.
 
Activate with Steam:
 
Ensure that you are activating your game through the Steam application. The Steam website cannot be used to activate a game.
 
1. Download and install the Steam client on your PC.
(https://store.steampowered.com/about/), then sign up and log in.
 
2. Locate the Steam key in your Pacgamedoc confirmation email, and copy it to your clipboard by pressing “Ctrl+C”.
 
 
3. Open the Steam client and locate the “+ ADD A GAME...” button on the bottom left of the window. Click this and choose the “Activate a Product on Steam…” option.
 
4. Paste the key from your clipboard in the “Product Code” section when asked, and follow the rest of the prompts to add the game to your library.
 
 
5. Your game is now viewable in the “Library” tab, and is available to download/install when you’re ready!

You can find additional support for the Steam client here: https://help.steampowered.com/en/wizard/HelpWithSteam