1) Scroll down the 'Control Panel' and click on 'State Sales Tax' under the 'Commerce' heading.

Steps 2, 3 & 4: Check the state you are required to collect sales tax in and enter the sales tax amount that should be charged for in-state purchases. For example, if your state tax is 5.25%, enter 5.25 in the tax amount field.

4) When you are finished, scroll down & click the 'Save' button