Most galleries are private URL’s. Once the link is shared with you, clicking on it will take you to an “Open Gallery” page. In the bottom right hand corner, click on the Open Gallery button.
Whether you are a gallery visitor or the gallery administrator, your email is used to create a unique access to the gallery. It allows you to save favorites and of course if you are the administrator, it opens up the additional tools available to you.
Typically galleries will be separated into Albums for ease of navigating to find specific photos you may be looking for or interested in. And of course you can click on the All Photos button.