Hello, sandyteji!
Not going out of scope of this add on, I could try to add additional field in the database with the id of the page where the calendar was opened and appointment was booked. But where and how to show this information is up to you.
“booking approved by user” needs adding some UI and changing the logic for it… Currently user can remove appointment if he can’t attend it. He will be infomed about new appointment by e-mail.
“we can pay for that booking?” – no, the payment gateways aren’t supported by this plugin.
Best regards!