Below is an example on how does it looks like on the backend:
Photos per row of Large devices - The number of photos for a row for large devices
Photos per row of Medium devices - The number of photos for a row for medium devices
Photos per row of Small devices - The number of photos for a row for small devices
Photo gallery image ,title and description - Add/remove the items of the gallery in this setting
Below is an example on how does it looks like on the frontend: