As Rue mentioned this page is not ready among or demos.
If I was to build this page I would do the following:
Go to Wp Admin > X > Install the Demo integrity 1
Go to X > Theme Options > Stacks > Select: Ethos.
Go to WP Admin > X > Install Revolution Slider
The Image above the navbar is a slider, you can create your own image, your you can download a slider demo from : https://revolution.themepunch.com/free-slider-exchange/ and import to your Slider Revolution.
After creating a full screen slider. Please add
.masthead to the container box ( it is the second red box on the image below)
Save your slider. Visit the home page, click Edit Page on your Wordpress Top Admin Bar.
On Wordpress classic backend editor, scroll down and find: Slider above masthead. Select the slider you have created.
Now Edit your page with Cornerstone and replace the place holder images with your own images and delete the sections you don´t need and build the new sections you want to.
Hope it helps