There’re 2 sections before your blog:
Step 1: Please create a new page, name it “Marry – Coffee Addict”, fill it with text content and set the featured image as the girl image you see on Rome demo front page.
Step 2: Go to Dashboard > Appearance > Customize > Intro page and select that page as intro page.
This is actually a widget. You can go to Dashboard > Appearance > Widgets and drop (Rome) Post Grid widget into Before Blog Sidebar. “Featured” is a category, you can select to display posts from any category you want.