- Upload the plugin's complete directory into the
/wp-content/plugins/directory. Simpleviewer is already included so there is no need to download it additionally. - Activate the plugin through the 'Plugins' menu in WordPress
- Click on 'Settings' and select WP-SimpleViewerto check and adjust your settings
Then you will be able to create new galleries under 'Manage' and then 'WP-SimpleViewer galleries'. For more information check this post.