Advice please for a new project

Some things in the user manual which might help are the Site Planning Tips and the Examples and Case Studies. You might also want to read the recent forum post (and linked blog) Omeka S workflow and customisations in a non-professional context.

In terms of importing from a spreadsheet, CSV Importer does need the files to be available online (and not password protected) in order to import.

Omeka is not really built for the digitization process - it’s built to share and contextualize the content once it has been digitized.