You may use the search box, upper right, to search your Gallery by date. For instance, enter the date of the session, "year-month-day", search and it will pull all Galleries for that date to make it easier to find.
Once inside your Gallery, to download all the photos at once. Please click the down arrow, in the top right-hand corner, beside the buy button. To download one photo, open the photo, look for a down arrow in the lower right part of the screen. Click it. All photos are free. Passwords are in lower case.