There are several parking options for Frick Park in general including off of Beechwood Blvd by the Blue Slide or at the Frick Environmental Center. The two closest for access to this trail are off of Forward Ave coming down from Beechwood Blvd there is a small lot just past the curve that contains the Irish Center of Pittsburgh,or taking Braddock Ave in Edgewood to Hutchinson and turning at Lancaster. Following Lancaster down the hill will get you to Frick's lower parking lot area.
To get to the trail you'll need to find your way to Nine Mile Run which is the creek that runs through the park. There is a singletrack that runs along the creek, and a green bench at the entrance to the trail where you'll need to ride or walk your bike across the creek.
The trail begins with a steady climb up to the fence line that separates the park from the Parkway (aka 376). From here the trail drops back down almost to creek level with a series of fun obstacles and options to take the expert (skull and cross bones line) or the beginner (chicken) line. Another climb up to close to the fence line rewards you with another challenging descent and another line choice. From here the trail rollercoasters along until finally dumping you off back at the creek upstream of where you entered.
Exploration is encouraged as there are alot of other excellent singletrack trails located throughout Frick Park.