I use schedule messages daily for parking fees, I need to create a few schedules, so I find it is not an easy process for the schedule, I used to use Samsung messages, and it was very easy.
1. When long pressing on the send button, it should open the schedule option (samsung and android have the same)
2. If scedule would be scroll for hour and minutes will be easier instead of selecting in the clock also the date could be next step not first step.
3. The list of scheduled messages should be displayed based on the scheduled time, not the time created