You’re right that you’ll want to use GP Hooks. However you’ll want the “After Header” hook.
To get your content to look like that, you’ll need some custom HTML and CSS.
<div class="grid-container grid-parent">
Your left side column HTML in here
Your right side column HTML in here
Then you would add your background image to the area using CSS:
background-image: url('URL TO YOUR BACKGROUND IMAGE');
Depending on the size and aspect ratios of your image and feature area, the whole image might not show – this is unfortunately just the way background images work in HTML.
Hopefully this is enough to get you going 🙂