Get start and end time of an activity using a form

I would like to use a form to enter date, start and end time of an activity.

Since there is no Hour option in the WorkForm, I am using the Date and Time for the start time and a Numbers column for the duration (in hours).
How can I then calculate the end time using a formula?

Hi Erez, Tom from monday here.

I was able to achieve a similar goal using the “format_date” and the “add_minutes” functions:

FORMAT_DATE(
ADD_MINUTES({Start date & time}, (MULTIPLY({Number of hours}, 60))),
“MMM DD, hh:mm”
)