Everything installed and ready to go? Alright! Click on the "Web" link at the far right of Lightroom's main navigation. This is where SlideShowPro Player for Lightroom is available to you for publishing your slideshows. Next, toggle open the "Gallery" panel in the far-right column. Select "SlideShowPro Player for Lightroom." The Lightroom interface should look similar to the figure below.
The "Template Edit Panels" are where you edit interface color, playback behavior, and other options for publishing. If you using the Lightroom 2 version of SlideShowPro Player for Lightroom, some parameter controls automatically enable/disable if they are related to the values of associated parameters. For example, if you were to choose the "Numbers" style for navigation links, any parameter control associated with the "Thumbnails" style would disable automatically.
The center "Work Area" displays a live preview of SlideShowPro Player for Lightroom. The preview updates whenever a change is made in the Template Edit Panels (if the parameter is of a visual nature), and is a WYSIWYG representation of what your slideshow will look like when published.
Finally, the "Filmstrip" contains photos from the currently selected Library folder, collection, keyword set, or contents of the Quick Collection.
SlideShowPro Player for Lightroom is built around the SlideShowPro Player, so it incorporates all of the same interface elements, behaviors, and customization options. If you've never used the Player before and would like a general overview of it, see the SlideShowPro Player section here in the wiki.
Any features that are unique to the Lightroom plugin -- including the Header and Popups player enhancements -- are here in the "Unique Features" section.