This doesn't look like my dashboard.
In order to add a custom teaser to your blog post please follow these steps:
1. While logged in to your Dashboard. Go to the My Content tab and click on the Blog option below then navigate to the blog post that you want to add a teaser break to and select Edit.
2. Find the Teaser field and type your custom text there.
3. To save your progress and to view the update without making it live select the Draft button at the bottom. To publish the update on the live website press the Needs Review button.