I didn't get that far with the indexing ... it's kind of overwhelming. The idea is that your index tells you where to look, and it can be anywhere. Not sure I like that, but it keeps you from constantly rearranging when you outgrow a category. For example, all stamps would be stored together and you add the newest to the end of the stash with whatever the next number is ... instead of going to file it with "florals", finding that your floral container is full and needing another container. Because who would think of purging anything to make it fit, right?!
I have my embossing folders stored together, numbered and made crayon rubbings for the index.
A small portion of stamps are indexed and point me to whether they are wood block in a cabinet, SU on a bookshelf or clear/cling in bins. My dies, I have put pictures of most in a folder in Dropbox so I if I'm in a store I can look to make sure I don't already own it!
Of course, I am not completely caught up in any category!