The theme is designed to work with the default Drupal content types, Article (article), and the Basic Page (page).
Let's say that you want to create a new content type Video Blog (video_blog) and use the theme layouts on it. To do that, you have to do some Drupal configuration and create a few template files which will inherit everything from the original theme files.
admin/structure/types/manage/article/form-display). This step is not required, but if you like to have a similar content editing experience with an article content type, you should do that.
In the sub-theme, duplicate the
themes/custom/em_magazine/content/CUSTOM_CONTENT_TYPE directory and rename it from CUSTOM_CONTENT_TYPE to your content type. In our case to video_blog.
Rename the template files so that the TYPE will be your content type's machine name.