Hi, the Bryce 7 manual can be found at this link (which you can find if you look under Bryce in the Documenation section of the site ):
http://docs.daz3d.com/doku.php/artzone/pub/software/bryce/start
That should give some guide to the different areas of the light lab. There are a whole range of tutorials on different aspects of lighting on Youtube aswell, but look through the links given in the Bryce Help topics thread (very useful!)over in the New Users help forum here :
http://www.daz3d.com/forums/viewthread/323/
If you have a specific query do post to the Bryce forum as there’s usually someone around who can help.