After creating and editing your Tiles in the Edit > Plan tab, there's one final step before sending them out - moving to Proof for final review. 

Proof is where you and other team members can do a final check before sending out the Tiles. You can make further edits if needed, and you can also drag and drop the Tiles into the exact order they will be sent (to see a preview of the email and text message, go to the Share tab). And if you change your mind and decide you'd like to send out a Tile at a different time, you can select "Back to Plan" to move the Tile back to the Plan section for a future date.