What to do to play offline version?

So sad to know this game will be gone in just 2 more days. I've been playing the global versions since day 1.

Done all the events and story that's avaliable, maxed out a load of the characters, I know I can't keep any of this sadly.

So I'm starting to wonder what do I need to do to prepare to play the offline JP version?

Do I need an account already setup on it? Or if I download it after it's offline will I still be able to make an account?

Even though I won't be able to understand the text I know this game we'll enough to know how it works and how to navigate the menus.