I hope this helps you get started if you're having trouble with volumetric lights. Click the download link on the right. It is a zip file. Within it are several sample parameters in a parameter folder, images and an html file. You have to unzip this file or the images in the tutorial will not display. Once you have it unzipped, click on VL Tutorial.html, and it should open in your default browser. Please fave this if you download it, it's such a little thing to ask to show you appreciate me taking the time to do it. Good luck!
PS: I forgot to mention that bib993 has posted a VL tutorial at this [link]