Hi and Welcome!
If you haven't read Mark's book yet, I recommend that you do, it will answer lots of the normal questions beginners have. You can get the same info by pouring through the blog and the forum, of course, but in the book it is all neatly laid out and accessible.
In terms of counting calories, I think it is a good idea to do so, at least until you have a firm grasp of how many calories you consume, and how many are in usual servings of your favorite foods. It really helps with portion sizes. I use FitDay, others here use Paleotrack. They'll help make it easier. I don't really use them anymore, except occasionally, when working some new food into my diet.
Best of luck to you!
David
Height: 5' 10"
Starting Weight: 292
Starting Primal Weight: 275
Current weight: ???
Goal weight: 172
Body fat: ???