When is the best time to make a baby? when your fertile or when your ovulating ?

Same thing.: When you ovulate (and for a short time after, ) you are fertile, and capable of becoming pregnant. At other times, not.

Ovulation timing: The optimal time for conception is 48 hours prior to and up to the day of ovulation. Therefore, start having intercourse a couple of days prior to when you actually ovulate and have intercourse every other day for a total of five times to help ensure sperm are there when you ovulate.