You can define as many different tax rates as required, together with the account names in which all the automatically calculated tax amounts will be accumulated.
Note that you must have set up the Tax Collected accounts in the Account Names List before you can specify the account name in the tax rates list. See VAT / Sales Tax accounting requirements.
Add new items by clicking 
or update existing items by selecting them from the drop down list.
Tax Name. You can enter any appropriate description for this tax rate.
Tax Rate. You should enter the percentage for this tax rate.
The tax description and rate that you choose will be displayed in the account item input dialog when you enter receipts and payments in a Bank or Charge account.
Tax Account You should select one of the Tax Collected accounts you have created.
The Tax account you choose will automatically accumulate all tax amounts calculated for the items that you enter at this tax rate. These amounts will be shown as a summary amount for each month in this account. You can get a detailed list of all tax amounts at this rate by clicking the 
button in the main toolbar in order to display all your VAT / Sales Tax transactions.
If you have selected Sales Tax in the VAT / Sales Tax options dialog, you will see a State / Provincial Sales Tax check box. On checking this box, you will see a second set of Tax Name, Tax Rate and Tax Account boxes.
By using the drop down list in this section of the dialog, you can add a second tax rate to be applied to transactions when the superior rate is applied. In this way Federal and State taxes are applied in the one transaction.
Before selection the subsidiary rate from the drop down list, you will need to specify it just like any other tax rate - above.