Daren has posted a really good video on astromechbuilder.com explaining what comes with a new dome and a little bit on how it all eventually fits together. Check it out at his gallery.
If you still need a dome, there are only a few left and they are going fast. Place your order now using the instructions at Astromech.net
Other pictures and info on one of these domes going together can be be found at John's blog.
He has some great pictures of his progress, and provides some great descriptions of his work.