The instructions are a bit unclear could you be more specific or include a video? I've reached to the page with the memories but my DLC's aren't unlocked so I'm a bit confused.
Here's a screenshot of all the folders you need to open and where you put the files. Start things off by right clicking the button that launches the Our Life game and choose "Show package contents". Then open all these folders and at the end once you've opened the "game" folder, you put the folder you extracted from the DLC in there. Make sure you extracted the DLC files and that they're not still in a zipped folder. I hope that helps!