Single tax rule for US-FL not working in local/test install, & diff. between taxes/tax rules?

[cpprod]

I'm just getting started with PrestaShop for the first time. In both Localization > Taxes and Localization > Tax Rules I've disabled all the others except for Florida. In Taxes, I have "Enable tax" and "Display tax in shopping cart" enabled, "Based on" invoice address. I created a Florida-based test customer and added an item to my cart, and am on the last step of checkout, still no tax added or shown. What am I missing? and what is the difference between the records in Taxes and Tax Rules?

Edited June 15, 2015 by cpprod (see edit history)