Photos and video are stored in galleries underneath your ALL PHOTOGRAPHS group. Settings on this group define your defaults for all other groups, galleries, and photos.
Consider creating multiple groups under ALL PHOTOGRAPHS to organize your galleries within. Everything under ALL PHOTOGRAPHS can be rearranged by dragging and dropping into a new order. You can also move or copy galleries into different groups, and photos into different galleries.
This video walks you through the basics of organizing your photos into groups and galleries, tag them for SEO, and add the links to your site menu.