When you arrive at Channing Circle, cross to the other side of the small park and take the trail up the hill. About 30 feet up this trail turn right onto Rollye Wiskerson Trail which wraps around the base of the hill as illustrated below. Note Rollye Wiskerson Trail is shown on most maps but there is no sign on the trail it’s self. 

Follow Rollye Wiskerson Trail about 600 feet and you will pass a steep trail which cuts directly up the hill on your left. Pass this trail and continue on another 100 feet and you will come to a second  trail trail to your left, follow this second trail up to launch as illustrated in the image below.