Basic map

Park either on the shoulder of Gilmore Trail (near the intersection of Steele Creek and Steese Expressway), or in the pullout at Hagelbarger on the other side of the Steese Expressway at the same intersection.

That's probably about as clear as mud.

Ride up, up up. You'll know that you've gone far enough when you run out of pavement. If you have a mountain bike, you can ride out the dirt part quite a ways and tie into other trails. See the 3D topo maps...