Connect VAT percentages with the taxes in Shopware.
Each row connects:
a VAT percentage, and
a Shopware Tax.
Good to know
Write the percentage without trailing zeros: 19, not 19.00, and 6.5, not 6.50.
Which tax to use is an accounting decision. Ask whoever does your bookkeeping.
If the list is empty, check that Shopware is connected. An empty list almost always means the connection, not the setting.