Flow leaves from the parking lot's far corner (you drive straight toward the Flow entrance when entering the parking area). It can be ridden either way and is lots of fun both ways. It is very flowy and has recently been updated. It includes small berms and fast flowing singletrack and is lots of fun to ride. This trail is not rideable after rain.
From I-40 take exit 388A toward James White Parkway, then continue to follow signs toward James White Parkway/TN-71 South. After crossing the river on James White, take ramp right to Hillwood Avenue/Sevier Avenue. From the off ramp, turn left onto Anita Dr. SE and continue straight (turns to Hillwood Avenue) until you reach a stop sign. Turn right at the stop sign onto Island Home Avenue then make an immediate left to continue onto Island Home. You can either park at Ijams Nature center and ride the greenway to the trails or drive past Ijams maybe .5 miles and park in the lot on the right marked by large rocks in the gated entrance (2-sided entrance) and a hump in the road where railroad tracks are.
http://www.singletracks.com/item.php?c=1&i=5553