Behavior of new tax classes, tax providers for new categories/products

All done through the admin interface:
1) I've added all new categories, with some subcategories. Within one of these subcategories, I've added a test product.
2) I've changed the names of the tax classes to match my categories.
3) Then I went into the tax providers and added the tax to the said categories for my state.
4) Deleted and then recreated one tax class
5) Added my state for tax in tax providers.

I go to checkout but the tax does not compute.

Suggestions?

OK, since removing a stupid question deducted 100 points (dunno what that's about), I'll answer this dumb question of mine instead of removing it like the other!

I had to go under the product and choose which tax class it fell under.