I've heard of some clever ways to start a coal fire in the stoker pot, such as embedding a used fuel oil filter into the coal bed, but here's how I started mine.
Turn the power off to the unit. Make a note of the air setting. In the picture are shown the check pawl on the left, painted blue and the drive pawl, unpainted on the right. Both are engaging the teeth on the gear. Lift up and rotate the drive pawl backward so it won't engage the teeth of gear. Set the air setting to (1) one.
Fill the pot about halfway full of coal. Place and light a fire-starter or kindling wood in the center of the pot. Place coal all around the kindling, up to the top of the pot. Once the kindling starts and has established a burn, restore power and turn on the stoker unit. The small amount of air will help stoke the kindling but coal will not be feeding in. Sprinkle coal on top of the kindling. Don't place too much coal on top of the kindling, but gradually add more coal on top of the kindling without smothering the fire. If the coal is starting to burn, turn the air setting up to (4) four and you can now put 1" of coal over the kindling. Momentarily turn the power off to the stoker, long enough to flip the drive pawl back so it engages the teeth on the gear, and the fire should continue to feed and burn automatically. Restore the former air setting.