Is it possible to add all available applications (which are missing on my LiberKey) in one single step automatically?

No automatic way, only manual (browse catalog)

Thank you Dji,

Okay...I have read

You can synchronize the display of the catalog with your LiberKey.
This can help you to locate applications that could interest you.

something about synchronization of the catalog on the website with your own LiberKey. I cannot get it working: when I click on in my LiberKey menu "Add applications" in my browser this pages opens: http://www.liberkey.com/en/catalog/browse.html. But how do I go on then?

Many thanks again. Nice greetings, Dirk