Upgrading from ThemeBuilder 2 to 3

Hello all,

I'm trying to make sense of the upgrade documention from ThemeBuilder 2 to 3.

We've upgraded Confluence from 2.6 to 2.9 which is forcing the upgrade to Theme Builder 3.

I have a test environment (Confluence 2.9 and Builder 3.3.2) now loaded with all our prod data .

I have about 400 spaces that each have their own custom configuration of the Theme Builder 2 theme.

Can someone give me the Idiot's Guide to the best way to upgrade these space configuration to Builder 3?

Thanks,

David