You can't find a tutorial for this anywhere? Have you tried this?
The right search terms can go a long way towards getting you what you want.
If you have Trapcode's Particular plugin, go to RedGiantPeople.com and search for clouds. There is a free project there that might be perfect for you.
found this http://www.redgiantsoftware.com/products/all/trapcode-particular/examples/, but no tutorials. Looked and looked, but no tutorials at all. Sorry I do have Trapcode Particular. I was trying to create the clouds halfway down the list, when the camera flys over the clouds.