You achieve this by building an extension or using the ones which are already existing in Qlik branch.
thank you very much for this answer! I tried both using KPI objects and adding an URL link to a Text&Image object and both versions worked very well.
I will also follow the hint for Navigation extensions (and I also got annother answer mentioning this), but as I am new to Qlik Sense, this will take some time.
For now I can use the KPI objects.
Extensions are surprisingly easy to use - download the extension you want, copy the folder into your Qlik install path and the extension appears on the left hand side of your "Edit" objects. (most extensions give a more detailed install guide)
Then, as with other objects there, you drag & drop and set properties.
Complexity increases if you decide to change the code of the extension or create your own.