Figure 8 Trail is Trail 500 on legacy maps.
Primary access is via the dirt fire road road on the south side of Knowlton Rd, and the road narrows to doubletrack. Look for the trail to branch off to the right to follow the route - you'll end up back on the doubletrack at the end of the ride. The trail rides well both ways, so you can go further up and bear left instead if you prefer a different riding experience.
There is an alternative connector signed for access to the Figure 8 Trail off Knowleton Rd, on MTB Project as Figure 8 Trail - Knowleton Road Connector
, which is a good exit, but not a great entrance to the trail due to steep grade uphill from Knowleton Rd to the Figure 8 Trail.
You'll encounter a section where the trails cross at a 4-way intersection, thus the name, figure 8. Just proceed straight through the intersection, and you'll eventually loop around and come back through. This applies no matter whether you're riding clockwise or counterclockwise.
There is a lot of dried pine needle cover on the ground and hilly terrain, these trails drain well and can be used shortly after rainfall without much mud.