Use pre-defined templates and layouts for your email, or learn how to create your own:
Creating an Email Design Template (this method allows you to use Skin Builder)
Using Legacy and Custom Design Templates/Layouts (this method gives you access to legacy email tools and templates, but not the Skin Builder functionality)
Also see Mobile Ready Email Templates.
Using Pre-defined Templates and Layouts
1. Create your email message using the Create Custom Email process and select Choose Template.
2. Select a Layout.
3. Select a Design Template. (The Design Templates that are available will change based on the Layout you have chosen.)
4. Click Save & Continue to Build Content for your email (or choose Done).