Sure – first, you’ll need to assign the Grid Page template to the page – looks like you already did that part.
Next, you’ll need to create some child pages of “Our Brands” so they will be displayed on the parent page you’ve already created. Child pages are also known as sub-pages.
To create a child page, first create a page.
Then, select “Our Brands” as the parent page. This is where you can select a parent page: https://cloudup.com/cGhPbGAS4N4
Be sure to add a featured image to each child page – that’s the image which will be displayed on the parent: https://cloudup.com/c925Ld6LvJC
Let me know how it goes!