The app uses due date/time, priority and then the homework description to order items.
If you like to break things down and they are all due at the same date/time with the same priority, then you can use letters or numbers to get them in order.
For example.
1. Research topic for paper
2. Collect citations
3. Create rough outline
4. xyz....
If those are entered as descriptions and they all have the same due date/time then, that order will be preserved.