Decide on the size of your oven. Select an area that will accommodate an oven of that size. Dig a pit that is as wide as you want your oven to be. It should be about 5 inches deep. Line the pit's sides with wood and fill the hole with concrete. Wait for the concrete to dry.
Build the fire encasement. Measure your brick and draw a line on the concrete slab that is brick's width plus two inches from the perimeter. Line three of these sides with concrete blocks. On the front side of the oven you will want to leave a blank space for the wood door. Now add your bricks to the outside of the concrete blocks. Stack them until they are about 2 feet high, putting mortar between each brick and block.
Build a wooden support on the inside of the fire encasement using 2x4s. Include a hole for the door. Lay a piece of cut plywood on top of the support and add another ring of 2x4s to make another concrete slab. Pour the concrete in and wait for it dry.
Build up with the bricks to create the area of the oven you will use to bake your food. Leave a door so that you can slide your food in and out of the oven.
Make a wooden template of the stone arch you want. Build the dome by laying the bricks sideways in an arch. Begin at the back and take your time as you follow the wood template. Wait for the arch to dry.
Finish building the oven by stacking bricks on the outside of the oven, leaving a small bit open for the chimney. Allow everything to dry and you are ready to start baking.