Tax class confusion

I’m having trouble setting up my ecommerce site so that it will charge the appropriate sales tax only to customers in my home state in the US. The instructions in the online guide seem to bear no resemblance to the actual tax setup page. Where I’m asked to set up a new tax class, save it, then edit it, the only option is to import a csv file. No dropdown box as referred to in the documentation:

In addition to country there are a few other variables can be set for tax. To see the full list, you should first save the tax pressing Add new tax button, then from the list press Edit button (available below the title on hover).
Here you will see a few more rows: State, ZIP/Postcode, City, Compound and Shipping Rate.
In state, zip/postcode and city rows you need to manually add the list of codes/names and separate them with semicolon to apply different tax rates based on filled in data. Plus you can have separate Shipping rate for the provided data.
The taxes use various attributes to define which tax should be applied to the product and in what order.

How do I set a simple % tax rate to be applied to customers within my home state?