The road is pretty easy and brand new almost all the way from Toyapakeh Harbour. You have to type Tembeling Beach and Forest on Google Map. From Toyapakeh, take the direction of Crystal Bay but turn left in the direction of Kelingking Beach at the first big intersection with a small temple in the middle. After a few kilometers take the second right (not the first one going to Broken Beach, the road is worse). And then it is almost staight on until you see the sign Temeling. It is a 40 minutes drive.
If you came with a driver you will have to hike down to Temeling Beach or ask a local people to drive you down with a scooter. If you came with a scooter the way down is very steep and impressive but it is easier than it seems. Park the scooter when you see the sign Parkir because the last section until the temple is indeed very steep and you my have difficulties to drive back.