Sea of Thieves - Mercenary Pack includes - Mercenary Pistol, Mercenary Cutlass, Mercenary Compass and Mercenary Outfit .
Mercenary Pack will be downloaded automatically after you redeem the code and install the game. You won’t have to manually install it or look for it in the store. However, you will have to find the items in the game – they won’t appear in your character’s inventory by themselves.
In order to get them head to the first outpost and check out all the merchants. One of them will be in charge of bonus items, and he’ll give you the Mercenary Pack items after you talk to him.