There is a web site just for you. It is called CADJUNKIE.com There are free RHINO tutorials on this site. It is basically a 6 week college course starting with the basics and ending by creating 3D objects. I think what you are looking for is in week 4. Here's a link:
<http://cadjunkie.com/1239/rhino-basics-week-04> Don't be shy, this is a good place to learn Rhino look around, you're certain to find exactly what you need.