Quote Originally Posted by Niwashi View Post
When you first loaded the game on PS4, you linked your PSN account to your SE account, so now Sony's PSN store lets SE's mogstation know when you buy or register an expansion. You only need to make sure the PSN knows about it (which is automatic if you bought it through the PSN, or done with a PSN registration code if bought from another retailer).
yeah, turn out that i have to quit the game then relog, so it gave me an option to link my account with my new purchase