If you don't have access to splits and want a more efficient cook, pretend the side fire box is the air intake. Build your minion fire on the end of cooking chamber closest to the fire box just like you would in a weber kettle. Use a brick or something to shield the fire from the food which will be placed on the exhaust end of cooking chamber.
It's easy, dump unlit coals in fire box end of cook chamber, bury a few half fist sized or larger chunks of wood in the coals. Toss a dozen or so fully lit coals on top. The fire should be stable in a matter of 15 minutes. Use the firebox intake to control temps.
I've had great success on that exact model of cooker doing it like that. Far better than with using the fire box.
Modded Brinkmann Gourmet. Basic UDS. Rescued 22.5" OTS. SJS Mini-WSM. Stubbs. B&B Oak Lump.
Cannondale 2009 F8 (for burning off all the great BBQ)