Don't understand where to put music or graphics files in a production

I have been migrating a huge Premiere project into a Production. I’m new to Productions.

I’ve been saving sequences as individual projects in the production. So far so good. But what I don’t understand is what to do with my project’s music and graphics assets. 

When I make a normal project, I make bins in the project that mirror the folders on my disk: 

02 Media

03 Graphics

04 Music …. and so on. 

So far, I’ve been migrating the “02 Media” sub-bins one by one and turning them into projects in the production. 

But what do I do with the graphics and music? I want these to be available to all the projects in the production - as they have been in the (very huge) project. Help! 

(I’ve been avoiding learning this for years, but with years’ worth of footage for this project now, it’s time to move over!)