there's 2 ways to go, one is through pandan indah/ampang, another is through hulu langat. But i recommend u taking hulu langat route coz it's easier for 1st timer.

Well, in cheras, just follow Kajang direction, you'll pass by phoenix plaza, go straight until you reach Rm1 toll, after the toll, turn to the 1st junction, follow Air Terjun Gabai/Sungai Congkak direction, go straight for about 8-10 minutes until you see a mosque at a traffic light, turn left, and turn left again go uphill. and there u go. The uphill road is just 3 minutes. Wallaa!! You reach look out point!