When you unlock an item in Assassin's Creed: Odyssey by redeeming a code or key (for example for a ULC or Season Pass), you will be notified by a message in-game that new items were unlocked.
You can check in-game if the contents were correctly unlocked. To do that, simply navigate to Store > Add-Ons. This screen will show you if your bonus content was unlocked correctly and if it was installed.
If you redeemed and installed a pack, the pack itself will display as Owned and the separate contents of the pack will be listed as Installed. Any Helix Credits you may have received will be added to your Balance in the top left.
The picture shows the contents of the Kronos Pack as example.
You may need to download and install the content manually. Check the FAQ for your platform (PC, PS4, Xbox One) to find out if that is the case.
Items that were correctly unlocked, downloaded and installed appear in your Inventory.
Any items that are not part of a pack or that you purchased for Helix Credits will be shown in Store > Owned. These will automatically be applied to the save game you purchased them with. However, you'll be able to use this menu to claim the same items for other save games.
If you cannot locate the content in-game, the information in this FAQ might help you.
Feel free to contact us if you have any questions!