When creating a session you can choose to have the system automatically create a gallery for you. This gallery will be created using the clients name once they have booked the session. This gallery will show up with your other galleries under Photos » Galleries. It will have the date of the session and will also be set as Not Currently Active. The gallery settings will be based on the Gallery Type you have chosen when setting up the session (*see details below). Once you upload photos to the gallery you can set the gallery to be active so your clients can see and purchase the images.
*To have the galleries automatically created you must have the Auto-create Gallery option selected when creating a Session Type. Please see this article on how to setup a Session Type. This will give you more information on how to Auto Create a Gallery.