How do I add tags to products?
I can't see anyway of adding new tags so that they can be assigned to a product in the administration
You need to define a tag and add it to a tag group which has been associated to a category in the category maintenance panel. Then if your product belongs to that category the tag group and tag should appear in the tags folder of the edit product screen.
How do I define tags?
Found it, under Localizations
Perhaps this is not the ideal section in the Admin App for these. We'll consider moving the Tag panels under Products in a future release.
This has been done for the next release... Tags and Tag Groups have been placed under the Products section, but it was done too late for this week's release (v4.1.0.0) - so for now you will still find Tags and Tag Groups under Localizations as you found.