How do I get the Main Email Body (default module) into a custom drag-and-drop template for RSS?

I’m creating a custom drag-and-drop template for email. I want to use this template for an external RSS email. However, I can’t seem to drag the default Main Email Body module into my custom template. I’ve tried cloning that module but when I use it my email I don’t have the option to Insert > Insert RSS Token. Nor do I have a field for RSS Feed URL.

I’ve also cloned a default template (Avast 1 Column) which contained the Main Email Body module, then I added my custom modules to make it structured how I want it. However, after publishing this template it doesn’t appear anywhere. I can’t find it when creating an email nor can I locate it when I search in the Design Manager.

Am I missing something? I just want more control over the design of the email by using my custom modules above and below where the external RSS will be shown.

Thanks!

Did you follow the instructions here? https://knowledge.hubspot.com/articles/kcs_article/cos-blog/set-up-an-rss-to-email-blog-subscription-for-an-external-blog