For driving instructions to the trailhead refer to the Devils, Flume, Pollock Bench, and Rattlesnake Canyon Trails portion of the Getting There section.
The trail begins outside the mouth of the canyon where there is a maze of dirt road-type trails. There is a map near the trailhead, but you can also see the mouth of the canyon so choose the roads that take the most direct route towards the canyon mouth. Once you reach Devils Canyon the trail turns into single track.
Once inside the canyon, the trail makes a nice loop of the canyon—first hugging one wall, then crossing over to the other wall for the return leg. There are a few short, steep sections of climbing but overall there is minimal elevation gain. The far end of the loop only goes a portion of the way into Devils Canyon, and one could spend hours blazing their own trail to explore the recesses of the canyon. Because of the arid nature of the region the ground cover is very sparse, eliminating the need for "bushwhacking." If one sticks to the loop, the hike is roughly 5 miles long.
There are opportunities for technical canyoneering in Devils Canyon. Scott has outlined one of these here
Only standard hiking gear is necessary. During hot weather, make sure to pack lots of water—there are no reliable sources of water along the way.