Extract the .zip file in your computer(You’ll get a .json file)
Now go to Divi > Theme Builder and click on + ( Add new Template) button and Choose 404 from the options and click on Design custom body and then select Build from scratch.
Now Drag the .json file from your computer and drop it the Divi Builder Page.
A popup will appear you may click on the checkbox(Remove existing content) and click the Import Divi Builder Layout button.
And you’re done.