Tap any task to view its details.
Once in the details view you can swipe left or right to view the previous and next tasks in the list.
Tap the number on the right of a task to view the list of subtasks.
From the task details view you can also tap the subtasks button.
View archived tasks
Open the top menu and choose Show Archived to view archived tasks in a queue.
From the archived view, open the top menu and choose Show Active to switch back to the active tasks in a queue.