Actually, there are none. But you should still do this hike. Depending on where you are starting from, it will take you about 1 hour to get to the starting point (I started from Kowloon Tong). You use the MTR and then the train – and when you go back the minibus and then the MTR. For further and better descriptions, follow this site.
What I can tell you, is that is called the little Grand Canyon. The only exhausting part is the first part, when you have to follow the street up, up and up.
But from there it only goes down again. Be aware, that you walk through an area of the military, so do not be afraid if you here gun shots.
I used the time to do some meditation. I tried that as well when I was hiking the Lion Rock, and similar to then it was not quiet but you could here cars and sometimes people walking by. Until, at some point, I could ignore everything. It was a great feeling.