BookDB3 is still in Alpha Testing
Many features are missing, and several of those which are present don't work.
I've put a test version online so you can try it out. You can install it on the same PC as BookDB2 - it won't overwrite your older version nor your data.
Once installed, use 'Create new database, and then you can import a copy of your BookDB2 data and try the various features out.
Remember, it's not ready for proper use yet.