How Can I Remove The Images In The 3 Boxes Under The Home Page Banner?

This requires CSS code. Heres is the css code and the steps below. 

.banners {

               background-image:none;

}

Here's how to apply the code: 

1. Login to your admin
2. Go to Storefront CMS 
3. CMS Features
4. Theme Settings
5. Custom CSS tab
6. Copy the code in blue above and paste it at the top or bottom of the "Global Custom CSS Code" box. 
7. Save/Update Layout 
8. Go to your storefront, refresh, and the 3 default images will be removed