First climb: Mount Olympia
Just past the trailhead gate, Donner Canyon Trail begins on your left. Take this trail and stay on it till it ends after about 1.5 miles at Cardinet Oaks Road. Climbing on this section is fairly mild; it gets mean soon enough.
Go left on Cardinet Oaks Road, which dips down to a creek crossing (which may be ankle deep during rainy season), then start climbing in earnest. After about 1.2 miles on Cardinet Oaks, the Olympia Trail marker appears on your right. Turn there.
This is when the real climbing starts. Olympia Trail zizgags up the hillside on a narrow single-track, then enters open terrain. After about a half-mile you'll hit the Zippe Trail junction, a left turn that'll get you to the Mount Olympia summit in about a half-mile. Your other option is to stay on Mount Olympia Trail, which is slightly longer. Both are calf-burner steep, so it's really a coin flip on which is the best route.