1. First, while on the "Welcome Home" page, select the "Ecommerce" module located to the left-hand side of your screen in the side-bar menu.

2. Next, in the drop-down list, select the "Settings" option, followed by "Store Settings."

3. You will then be prompted with the E-commerce "Store Settings" page. 

4. From the settings list select the "Tax Classes" option.

5. The "Tax Classes" section will expand, allowing you to alter your Tax Class Settings listed below.

Tax Class Settings

When you choose to add a New Tax Class...