Jim,
You will need to use a flght planner that supports exporting to a GPX file. Save that GPX file to a USB thumb drive, then insert the USB drive in the the iFly 720. On the iFly 720, go to Flight Plan and touch Load, you should see that saved flight plan in the list. Touch it and touch Load. You can then fly it, modify it, or save it to the device.
I hope this helps.