Select the document for which you want to set the document status and either double-click on the entry or on the "Document properties" icon.

Now select the 3 tab "Tagging" and the area "Document status".

Now you can choose from the status entries that come with the installation or create your own by clicking on "Edit document status".
After you have selected a status entry, save the changes by clicking on the "Save change" button below.
You can see that the status entry in the document list changes according to your specifications.