Templates from template editor (and all changes made to them) are saved automatically. The templates are stored in the “custom templates” section.
There is always at least one template (My template) available in this section. To start editing one of our default templates click “copy and edit in editor” link and a new template will be created.
When working in the editor use “Undo” or “Change history” links to access previously stored versions.
Please see this topic for more information about template editor.