All tasks are sorted by the date and time when they were added. So each new task is added to the end of the list.
The tasks are organised in pages. Pages contain equal number of tasks, except for the last one where tasks are still being added.
As you turn pages, the next page (right, →) will take you to the newer tasks.
The previous page (left, ←) takes you towards the older tasks.
When a step of a task is completed, a new step is added at the end of the list, to the last page.