How to activate VAT?

-- url of the page with the problem -- : www.politikchronist.org
-- HikaShop version -- : 4.4.4
-- Joomla version -- : 3.10.3
-- PHP version -- : 7.4.20
-- Browser(s) name and version -- : Firefox 94
-- Error-message(debug-mod must be tuned on) -- : How to activate VAT?

When installing the shop I managed to deactivate the VAT calculation, because in Germany we had the possibility for small business to choose "no VAT". Now from 1st of January I should activate the VAT but I do not find the right button. I cannot find where to define the "Default tax category". Sorry help urgently needed

I can chose "Default Tax category" or "Non" within the product description, and "Steuersatz" i.e. tax% is deactivated.

Thanks a lot. The problem is, that I cannot enter any rate for the Default tax category. When clicking on "rate" I cannot enter any rate. And I do not find the way to define rates. So stupid me.
I found on the help site:
"Then, by clicking on the Manage rates button on the taxations rules screen ( you will see this screen of you click on cancel on the page for which this documentation is for ), you will be able to create tax rates. For example you will create a rate of 5% which will be used for food sales and a 20% rate for electronics."
But there is no "Manage rates" button when I leave the page as described .... Something is missing ....
puuuuuu I found it .... I found the manage rates Button. .... sorry to bother you folks. The button was on a position I did not expect...
SORRRY