Is it even possible to convert a single line field to calculate start time and end time in zoho? I would also like to add a time for lunch as well.. Example 30 minutes or 1 hour lunch to subtract from start and end time.

I have found a few resources online like https://app.zohocreator.com/martryl/date-time-functions#DateTime but I cannot figure out how to do this without implementing the date-time field. Is this possible in Zoho Creator? 

I'm working on building a timesheet application that my employees can use to calculate start time and end time.