There are many designs for smokers...... What style was your original thought.... It seems to be a mix of different designed smokers....
I notice you have no tuning plates, which would be appropriate for that smoker... Then the stack "plenum" would be placed above the cooking grate...
If you wanted a Reverse Flow, the stack would be placed above the firebox, just above the cooking grate....
A Jambo, the fire enters the cooking chamber above the cooking grate and the exhaust is below the cooking grate...
Dave