1) From the Projects screen, tap the Project you wish to work on. This will bring you to the Project Summary.
2) From the Summary screen, tap "Edit Issues" to go to the issues list.
3) Tap on the "Edit" button, located in the top right corner of the screen.
4) Tap and hold on the three lines to the far right of an Issue, then drag it to the position you wish to place it in the list.
5) Tap Done in the top left to confirm these changes.