Your outbox can be found under Emails > Outbox. This is where all of your single emails (drafts or sent messages) from Spark or BCC emails are stored.
Click on the New Email icon to start a new message. With single emails, you have the option of using "Quick Compose" or "Template" - Quick Compose is our regular editor, much like what you are already used to with your current email client, whereas Template enables you to use your Carpenter templates on a one-off basis. There is also a special kind of template that you can only use in single emails, called Open Content templates.
Open Content templates are designed just like regular templates, only they include a special Open Content widget (see Carpenter) that enables you to customize the body of the template while retaining your design. When you select an Open Content template from your template list, a preview of the template will appear below the text editor. Write your email in the text editor, and the template preview will update live.