This is really easy and simple to do and falls within setting up your Templates.
When setting up your Templates simply select the relavent Day and Time to send your email.
- Day - selecting '0 day' will be on the day you hit send. For all follow up it will be X amount of days after the previous email to send.
- Time through either AM (9-11am)/PM (3-5pm) of which the timezone in your account is set to.