To send content to a user, you must first create that piece of content, whether it be a Policy, Survey, Phish, Course or Blog. When the content is created, you must select it from the 'Choose by Type' drop-down, and then select the specific piece of content that you had created.
When you add your step into the Campaign, you must allocate a date/time for the piece of content to go live:
When you are ready to publish steps out to your end users, you must click into the Targeting tab, and select the users from the Target search bar; you may have department groups created, so you can target specific groups or select all staff. Finally, you then click Publish Changes in the top right hand corner of the screen, and the content will be delivered at the date/time you have allocated.