Connect the tax (VAT) rates from your ERP with the tax classes in WooCommerce.
Each row connects:
a Tax Rate, written as a number, and
a WooCommerce Tax Class.
Good to know
Write the rate without the % sign. For example, a 25% tax rate is written as 25.
The list of tax classes comes from your WooCommerce.
Which tax class to use is an accounting decision. Ask whoever does your bookkeeping.
If the list is empty, check that WooCommerce is connected. An empty list almost always means the connection, not the setting.