Weld that flap under smoke stack shut, put a latch on other one ( it for ash clean out) plate off top half of that opening from firebox. Running it with exhaust 3/4-full open, get a bed of hot charcoal coals then add a split log (1/4 log) every 45 minutes - 1 hr . Wood Burns Hotter than Charcoal.
this can be a decent smoker with minor work.
Check out tuning plates on YouTube - several styles to try