Every task in your space is tagged with the task tag by default. You tag it with additional tags by using Tag in the task name, e.g.
And can then be queried via either task or upnext.
The following query shows all attributes available for tasks: ${queryfrom index.tag "upnext"}
Although you may want to render it using a template instead: ${template.each(queryfrom index.tag "upnext", templates.taskItem)}
Specific attributes:
* done: set to true of the state of the task is “checked”
* state: the text of the state (useful for custom states), see ^Library/Std/APIs/Task State
Additionally, tasks inherit all attributes of Object/item.