To get there we follow the 106 from Taipei towards Pingxi 平溪. After a while there is a hairpin bend with a small tunnel on the apex of the bend. Go past this and then through a small tunnel. After this, look on the left for a turn off that leads up to a temple. There’s a sign in English and Chinese but you’ll need the eyes of a hawk to spot it!
There’s nowhere for food or water and so you need to bring it.
There are buses that run from Mucha out to Pingxi but I don’t know if they stop near the turn off the Yuanming Zen Temple 圓明禪寺.
A rough map of the area can be found here at Tony Huang’s blog.