While intermittent fasting is not necessary or required, if you are looking for fat loss, you may implement a schedule of 16:8 intermittent fasting, meaning restrict your eating during a window of only 8 hours per day, on most days of the week.
Regarding when to start implementing intermittent fasting, it may be recommended to not try to make too many lifestyle changes too fast or too soon. Give your body time to adjust to starting a new daily habit, then, after some time the appetite suppressant may start to take effect, thereby making the new routine of intermittent fasting, easier to phase into your lifestyle.

Learn more about the benefits of intermittent fasting here and here.