You can create so-called custom fields in the various applications (e.g. address book, calendar, InfoLog and Project Manager) which in each case appear in the User defined tab (window). These fields must be defined in every application separately from the system administrator.
How to create and edit them is desribed in this page.
How to make use of your CustomFields in your Applications is described in Code Corner.
User Manual / Administration
The user manual is written by Outdoor Unlimited Training GmbH, who also offers support together with Stylite AG, see eGroupWare support.