I’ve answer your first questions via ThemeForest. I’m sorry very late reply you, but I will move all discussion via this support forum.
The Gallery like on http://www.thememaha.com/curated/technology/scelerisque-ullamcorper-aliqua-sociosqu-blandit-quis/ is just regular WordPress Gallery but converted as new layout with Curated theme.
When creating a post, click the ‘Add Media’ button, create a gallery, choose your images. Then insert the gallery into post. Update/Publish your post.
Hope this helps,