To update the relevant tax rates for your property to go "Rates > Tax Rates" in the menu.
You can add any number of tax codes that are relevant for your business. E.g. 'Low' or 'Standard'. You do not need to add the 0% rate or N/A rate as these are available in the system by default.
Simply specify a label for the tax code, the % amount e.g. 9% and a date from which the rate is valid.
If a tax rate is changed in your country you can add a new rate to an existing tax code and specify the date at which the new rate is relevant, e.g. 1st of Jan, then you can continue to use the system and on the date the new tax rate should be applied, the system will automatically use it when generating customer bills.
When creating an upgrade/extra or configuring a new type of accommodation, you can specify which tax rate should apply to the product. Guest bills will reflect the relevant tax rates at the time of generating the bill.