The appointment screen is very cool and intuitive, but you need to further develop the backend options, such as:
1) allow to add more rows of schedules per employee, to be able to differentiate service schedules on different days of the week;
2) Dashboard screen with the schedules marked, with client name, time, service, employee and status (confirmed, canceled, to be confirmed);
3) Allow employees access to view and change their schedules if needed;
These 3 changes are what I believe are more urgent, but congratulations for the development and thanks for making it available for free!