Give your Campaign a name (and description if you want) and click Save.
On the Campaign page, click Campaign Steps and then Add a Step
Enter the subject and body of the message. Use the Insert Field link where you want to put in candidate-specific fields like the candidate's name. You'll see a placeholder appear. The placeholder will be filled in with the candidate's information (or current day of week).
Create as many steps as you want and specify the number of days between steps. When you've finished editing the messages, click Save.