This trail circles the mysterious crater. About 100 yards up the trail, the Upheaval Dome Overlook trail goes straight, and the loop trails go to the left and right. If you're going the clockwise route, as described here, take a left. Then, you start a steep descent into Upheaval Canyon. For the next mile, the trail drops abruptly.
Some sections are rocky and rough with short switchbacks, but it's still easy to follow.
Most of the 1,300-foot elevation loss occurs in this mile. This is a fairly good reason to take the route clockwise. You'll notice that the climb up to the trailhead on the other side of the crater is not quite as steep. Follow the canyon wash for about another mile to the junction with the Upheaval Canyon Trail. Here, the Upheaval Canyon Trail takes a sharp left and heads off to the west toward the Green River.