- Extract lightbox-plus.zip to your wp-content/plugins directory.
- In the admin panel under Plugins activate Lightbox Plus.
- In the admin panel under Design/Appearance click on Lightbox Plus to configure to your taste.
- It should now be completely set up and functional
Caveats
Flash (i.e. YouTube videos, etc.) will sit atop the Lightbox Plus display not matter what the z-index is. This is an issue with Flash.
See Flash content displays on top of all DHTML layers at Adobe for details.
To work around this issue you will need to add something like the following to your <param /> and <embed></embed> tags:
<object><param name="wmode" value="opaque" /><embed wmode="opaque" [all other embed settings, file src etc.]></embed></object>
