Xwiki Create virtual wiki - problem adding a class

I'm trying to create a virtual wiki but I already struggle with

In your Class Editor, create a new class called "XWikiServerClass"

Further reading in the DevGuide / DataModel shows that I'm not alone. I understand the words saying but I don't get the how-to as there is no option in the class-editior of creating new classes. Navigating to class editor shows an info box

No class is defined in this wiki document. You can create one by adding properties from the panel on your right, or you can choose another class to edit from the list below.

Ok, I added 'XWikiServerClass' and would have expected to be able to add a type class but that's not possible. I've tried a few properties but nothing shows up as a class in cl开发者_StackOverflow中文版ass editor.

Can you give more info on how you set up your wiki ?

As far as I know, you should have installed xwiki-enterprise-manager-web-x.y.war and modify your setup to fit your needs.

Second, you should have imported "xwiki-enterprise-manager-wiki-administrator-x.y.xar into your empty instance.

This xar archive already contains the XWikiServerClass and a very handy set of pages to automate the creation of virtual wikis.