Hi there,
so the WordPress home page can either be a Static Page or set to Display your recent Posts (Blog). Volume was designed for blogging and is therefore set to the latter ( ie. display posts ).
So you can either:
1. Add some new Posts with featured images, these will fill the home page automatically. And delete those Posts that were imported with Volume.
OR
2. Go to Dashboard > Settings > Reading and change the Homepage to display a Static Page. You will need to create a new Page first before doing this. Now your new home page can be edited to display whatever you want.