help the dlc won't work

[GodYod]

I have the dlc installed for the game but whenever I open the game and go to the dlc page it says go to steam store, there's no way for me to download it on the steam store it knows I have the dlc and it is installed but no matter I do it wont work I've tried uninstalling the dlc then reinstalling it and nothing works, also now whenever I open the game it starts playing the audio from the game trailer and I can't stop it. Someone please help me I think my game is possessed.

[IzunaDrop]

The DLC appears in game once you beat the final boss. You will see a blue cube floating near Adio's house.

[GodYod]

if by final boss your referring to the adio and robot fish thing fight I've beat them and the dlc still won't appear

[IzunaDrop]

You have to actually finish the game. Talk to Lim, tell her you are ready to set sail, and then once you see all the end credits etc., the game will allow you to make a save. Save your game and load into that same save file, the blue cube that gives you access to the DLC should show up then.