If you haven’t already done so, make sure you add a DocuGen view to your board.
You can generate a document at any time by going to the DocuGen view and clicking the “Generate document” button ("Generate" button in case of DocuGen item views.) Your new document will be ready within seconds.
When you click on the “Generate document” button, a new document is generated immediately based on the DocuGen view settings. You can also use a template when generating documents.