Greetings and welcome to the AC Board. I hope you'll continue to try AC and let all of us know your feedback.
Regarding a "place-holder", I suggest using the same method that is used to block out time on the appointment schedule for meetings, time out of the office, etc:
1. Click on the schedule button on the upper left of any AC window to open the day's appointments, which now appear on the right half of the window.
2. Click on the provider's name just above the first appointment time. The schedule opens to the provider detail view.
3. Move the cursor into the far left column of the appointments, just to the left of the time that you wish to reserve for the new patient. The cursor changes to an arrow.
4. Click the cursor, and the row at the selected time becomes highlighted.
5. Click on the "Block" button on the top left of the schedule, just above the Time column. The "Name Your Block" box opens. Enter the patient info and click "OK".
6. The patient info now fills the time chosen, but you didn't have to fill out the Demographics.
This is a really great question, so I added this to the Amazing Charts
Wiki Encyclopedia.