WARNING: Gallery is a Beta Module. Do not use for production.

First, you will need host permissions to install the module: Click on Host>Module Definitions. Select from the dropdown menu "Install New Module" then browse your file system and select the Install version, click on Add and when the module is listed in the window below, click on Upload.

To add it to a page you need to follow this steps: http://www.dotnetnuke.com/guidedtour/ModulesAdd.htm

Then Configure it: http://www.dotnetnuke.com/guidedtour/HelpGalleryConfigure.htm

You get access to the Host Menu when you login as the Host user.