Traditionally, the camembert is removed from its box, all the wrappings and labels taken off, then it's carefully placed back in the box (or in an ovenproof dish), with thin slivers of garlic and springs of thyme poked into it, the lid or some covering placed back on top of the box, then it's heated through in the oven for just 5 to 10 minutes until the cheese has melted.
Here's an unusual way of serving it that doesn't use garlic though:-
http://www.marieclaire.co.uk/lifestyle/recipes /170272/baked-camembert-with-focaccia-croutons .html