To use previously prepared email campaigns (still in draft) you need to send those campaigns out. So the way to do that is to add yourself as a contact in your account (preferably with a different email address to your login email address), add email contact preference to your contact, then select your contact only and then send your email campaigns out immediately.
Once those emails have been sent in that way you will be able to select them from the drop-down list and then clone them to use in your automation.