How to set the custom date value to Activity Start Date field

Summary:

We have a requirement to book the slots as per the availability so as per the selection we need to book the appointment.

Based on the selected Date and Time we need to update the Activity Start and End Date , but unable to update the fields with desired values

Content (required):

In below new_time we have our date and time and formating using format method.

Ex 1: def new_date = new Date(new_time).format("yyyy-MM-dd hh:mm a") 

setAttribute('ActivityStartDate',new_date)

Ex 2: def new_date = new Date(new_time).format("yyyy-MMM-dd hh:mm a") 

setAttribute('ActivityStartDate',new_date)