Fire It Up!
I would start with everything wide open, build a coal bed in the firebox side closest to the cook chamber with lump charcoal and a few splits.
Once that's established and running thin blue smoke, close the cook chamber door and the firebox lid.
Once it's drafting well, what's the cook chamber temp settle at? Over 300*F is a good thing. I would close in this order, fire box intake, damper between FB and CC, CC exhaust to achieve your desired CC temp.
If closing the FB lid chokes the fire, prop it open a little for now and plan to add more intake.
It's a great looking build, kudos to you :clap2: