/wp-content/plugins/lis-video-gallery
directory, or install the plugin through the WordPress plugins screen directly.Sure, you can use this plugin for many pages, because it uses shortcodes. You can create infinity amount of galleries. Using shortcode you can define any gallery for any page.
It's OK. Thumbnail would be generated automatically. = What is the sense to use Popup Box = None option? There is no huge sense. No one popup box isn't set because we don't want to make any default popup box and make decision for our users. Also you may want to use video gallery type, but without loading additional libraries in face of popup box. = What is the sense to use Load From = Do not load option? If you already using on chosed library for popups, you don't need to load it anymore. So, you should chose "Do not load" option.