Make.com Appointment Booking Automation

I need a fully-automated scheduling flow inside Make.com that lets a visitor choose an open time slot, enter their phone number and address, and instantly finalises the booking without risking double-ups.

How the flow should work
• The visitor lands on a Make-generated (or embedded) form that displays only the currently available slots.
• Once a slot is chosen, the scenario checks real-time availability, locks the slot, stores the record in my Google Sheets CRM file, and triggers a push notification confirming the appointment.
• Additional push notifications should go out for reschedules, cancellations and a reminder shortly before the meeting.

Key requirements
1. Slot management logic that truly prevents double-booking.
2. Clean data push into the correct Google Sheets columns so I can run reports later.
3. Branded push notifications (confirmation, reminder, update) sent via whatever push service you recommend; they must pull dynamic data (name, slot, location) from the sheet.
4. A simple way for me to adjust available times or pause the calendar without touching the underlying scenario.

Acceptance criteria
• Selecting an already-taken slot is impossible in the live form.
• On submit, a new row appears in Google Sheets with the visitor’s phone and address plus time stamp.
• Visitor receives a push confirmation within 30 seconds.
• System can handle at least 50 concurrent bookings without conflict.

Let me know which push platform you’d link (OneSignal, Pushover, etc.) and any prerequisites I need to line up before you start.