If you need taxes beyond primary and secondary or need to be able to support three decimal or 'tax on tax' tax rates you can set them up as an extra tax via the 'Add Tax' button.
In this section add a unique Tax ID followed by a brief description. Choose a flat rate or a percentage rate. Enter the rate as a number. Select whether this tax will be applied on top of other taxes (a rare occurrence). A Nonrecurring Tax is intended to be a one-time tax for a booking. If the tax is applied each day of the stay, it is Recurring. Note that managing daily taxes is only applicable to users of the Property Management Systems.