While building an automated email journey, you may see an "Incomplete Steps" warning. This means some information is missing, and you won't be able to save and turn on your journey until you complete it.
If you have this warning, it's likely because you haven't filled in all the required settings for one or more emails in your journey.
To fix this:
Look at the left-hand column for each email step in your journey.
Make sure you have a Step Name and a Subject.
Confirm that you have entered the from name and from email address for each email.
Once you fill in all the details for every email step, the "Incomplete Steps" warning will disappear. You can then save and turn on your journey.