To add pictures, first (1) click "Pictures" in the left-menu to go to the Pictures page. Then (2) click the yellow "+ Photos" button on the right. When the "Add Photos" page comes up, (3) click the "Select Photos" button to upload your pictures. Several pictures can be upload at the same time.
After your pictures are loaded, (4) on the Pictures page click any photo to open a large picture popup, then (5) click the small blue "Edit" button (at the center-right of the large picture) to add/edit the descriptive information about each picture.