How a record's details are displayed is defined in the RecordView page. You can add a RecordView page only to a record's context-specific menu action in the Context Menus area. The RecordView page is usually called by the predefined SHOWRECORD menu action that displays the record clicked in a list with the default Expand Page Configuration.
The Expand configuration defines which field group and header group is used.
To define the Details page:
The menu's configuration is displayed.