Mary, I also have a Holland Companion grill. I have had it much, much longer than the Cobb. The principal of how to cook on the Cobb is very much the same. If you go to the Holland website and forums, you will find a ton of ideas.
This is a grill that works the best with the lid on, for the cooking time. It keeps the heat inside and allows meats to cook completely while retaining wonderful moistness. You don't even HAVE to flip it.
The more often you remove the lid, the longer it will take and the more charcoal you will end up needing.
You can even bake beautiful bread in the Cobb with a wonderful, golden, crusty crust. I posted a picture of the very first loaf I ever made on it, on this thread, I think.
You will get the hang of it and love it.
Also, if you decide not to go with the disk charcoal and don't order any of the clean burning coconut kind, I have found GFS charcoal to do a much better job than Kingsford. It is much larger chunks and lasts for those bigger roasting jobs.
I did not get a cookbook. I just did a search for Cobb Grill recipes and got the jest of it. There are a lot of videos on youtube, people have put up using the Cobb.