The Vegas Slideshow presentation type can be used to create an inline slideshow, or a full-screen slideshow in the page background.
The slideshow supports auto-play, next/previous image navigation, and a variety of other options, and makes for an excellent splash screen for visitors to your website.
To create a full-screen slideshow, you should first create a full-screen page template.
Then, edit an existing album template, or create a new one using the Theater Add-on. In the designer, under Album Setup:
At this point, you should probably publish a few images so that you have something to look at, then return to Backlight to set your preferences as you like.
After creating a Vegas Slideshow gallery, as above, return to Lightroom's Publish Services and edit the album's settings thus:
Return to Backlight. In Backlight's menu, go Designer ⇒ Pages.
Your Vegas Slideshow is now your Home page!