You can access and import pre-made layouts directly from the Divi Builder when creating or editing a page.

When you add a new page from the WordPress Dashboard, deploy the Visual Builder.

If this is a new page, you will be prompted with three choices regarding how you want to start building your page. Select the option “Choose A Premade Layout”.

This will automatically launch the “Load From Library” popup where you will find all the pre-made layouts.