Hi,
You need to go in the menu System->Taxation and click on the "manage tax categories" button.
Then, create a tax category.
Then, go back to the taxation screen and click on the "manage tax rates" button.
Then, create a tax rate.
Than, go back to the taxation screen and create a new tax rule. There, select the tax category, the tax rate and click on save.
Then, edit each of your products and select the tax category.
Finally, make sure that when you display listing of products as well as on the product page, you display the prices with taxes. Check for that the prices option in the configuration under the tab Display, and in your products listing menus/modules' options via the menus Display->Content modules/menus.
You can change the text after the price easily. By default it's "per unit" but you can put whatever you want. Go in the configuration under the tab "Languages" and edit your translation file. There, near the top, you will find the "per unit" translation text.
You could put your text with a link on it:
PER_UNIT=" <a href='LINK_TO_A_JOOMLA_ARTICLE' target='_blank'>zuzüglich Versandkosten</a>"