First of all, thank you for your support and for purchasing the DLC; it means a lot!
If you purchased the DLC directly in your Steam, navigate to your library on Steam, right-click Gray Zone Warfare in the list of games, and select Properties. Finally, open the DLC tab, and check if the DLCs are present there.
If the DLCs are present, all you need to do is start the game, connect to a server, and check the messenger. You will have received a message(s) from Handshake with your DLC rewards. Your locker size will be increased automatically.
What to do if there are no DLCs displayed under the DLC tab?
Check your account's purchase history to make sure that your purchase was completed correctly. Follow this link to open your Steam account's purchase history. If the transaction was completed successfully, but you don't have the DLC in your account, send us the details using our support form, and we will help you get your rewards.
What to do if you purchased the edition upgrades at a 3rd party store and did not receive the rewards?
Editions are essentially DLC bundles, and depending on the edition upgrade you purchase, you should receive the appropriate number of Steam keys to redeem. If you purchase the Supporter edition upgrade, you should receive 3 Steam keys in total (one for each Tactical, Elite, and Supporter DLC). If you purchased the supporter upgrade and received only one key, contact the seller and request the additional keys for the other DLCs.