Is it you just can't see the Tags and captions pane ? Alt+HT or View section Tags and captions pane.
Add categories should be listed.
If you want to see a complete list of existing Descriptive tags,
Go to the Find section and click on the lower portion of the Tags button for a list,
Alt+DT
Once upon a time all of the Tags were listed on the Left side column,
It was removed but you can add it back,
Click on the Blue file button, and click on Options,
General section, near the bottom. Navigation Pane, check the box Show Descriptive tags, save.