To be able to publish your products from the Spreadconnect App, you need to set up your tax rates in your WooCommerce settings.
Before creating any tax rates, we highly recommend to you contact a tax advisor. They will be able to set the right rates for you.
To set the tax rates, go to your WooCommerce account and click on Settings -> Tax -> Standard Rates. The tax rate depends on a few factors, such as where you are selling to and what kind of business you are. For example, if you are selling within Germany and you do not have any tax exemption, the usual tax rate would be 19%.
Once the standard rates have been set up, you need to assign the applicable tax rate to a product.
All of those rates will be used by WooCommerce during checkout to calculate the right amount of taxes charged to your customer.