Use the lid of your Dutch Oven (DO) as the base. We'll place the pan over it later. This will serve as the oven, as we'll be placing briquettes above and below.
Step 1 : Prepare the pizza dough according to the recipe. Allow for the dough's rising time, so start early. You can also use a roll of fresh pizza dough. You'll need to cut it to size.
Step 2 : Now light your chimney starter with approximately 20 briquettes in it (for a 4.5 Qt Dutch Oven, 16 briquettes are enough). 
Step 3 : Turn your Dutch oven upside down and place it on a flat, sturdy, and fireproof surface. Then place about 6 briquettes underneath and the rest on top to preheat. Be careful! The bottom of the pan doesn't have a raised edge. Keep this in mind and ensure no briquettes fall off. 
Step 4 : Cut a piece of baking paper to the size of your lid.
Step 5 : Roll out your dough to the size of your baking paper and top it as desired.
Step 6 : Carefully lift the pan off the lid and place the pizza in/on the lid. Then replace the pan. Be careful, as the coals can easily fall off.
It'll be boiling hot, of course! So wear fireproof gloves.