It is possible to reorder tasks inside PublishPress Checklists. This will change the order in which tasks appear in the sidebar of the post editing screen.
In the image below, you see that the “Number of characters in the title” task is being dragged lower down the list. You can do this by selecting the row you want to move and dragging-and-dropping it to a new location.
Normally the “Number of characters in the title” task is first on the list of tasks. However, now when you go to edit a post, you will see that task is lower down in the list of tasks: