To to the image archive. (Click the upper right corner on the navigator)
Highlight the desired folder to use in the Image explorer. Select Properties on the folder.
Select the tab Metadata and click the button "Add metadata".
Choose a metadata of the type Multiple selection. Beneathe the tab General you add the following:
Description: Here you add the name used in searches in the image explorer e.g. category.
Name: Here you add a meta name e.g. imagecategory
Scheme: Describes according to which scheme the tag should be written with. The field is left empty.
Beneath the tab Alternative you add the different alternatives you can choose between in the multiple selection e.g. People:
In order to add an alternative you click the plus sign. A new window will open where you add an alternative.
Beneath the tab Search you check both alternatives:
Beneath the tab Advanced you check the following:
Force new values on each page (inheritance blocked): If this setting is chosen the user will not be able to inherit values from pages above. This setting should be used if the user must add a value for a field and can not be fetched from another page.