full calendar business hours(available date and time) set dynamically through date picker

Question

I'm using FullCalendar and datepicker to set the availability(date and time) for the user. Once the user click on date and time (I'm getting fromdate,todate,fromtime,totime) the area should be available to book appointments and the rest of the area should be grayed out and unavailable to book the appointments. I've tried every way mentioned in the full calendar docs also the ones mentioned here.How to pass the values selected in the date picker to the fullcalendar and set the availability? Any help would be appreciated ! thank you in advance!