For anyone who has not been to Sai Wan before, the access is through Sai Kung town. From there, depending on your arrival time, you can take the 29R village bus, though it has limited times. Follow this link for more information: 29R Bus Timetable.
If you are not able to make those bus times, the only other way is to take a green taxi to “Sai Wan Ting” pavilion, costing about $100. It is a popular spot, so the taxi drivers will know it. During peak times, it will be difficult to get a taxi to go there, since they all want to go back and forth between Sai Kung and the city areas for more fares. Plan accordingly.
When you reach Sai Wan Ting pavilion, there is a paved and well-marked hiking trail on the left hand side of the road, across from the pavilion. There are also portable toilets a little bit back up the road that you will pass just before the pavilion when coming in. This spot typically has no phone signal, so you will not be able to alert us to your arrival there.
Take the paved hiking trail all the way down to Sai Wan village. There are no turns, so it is impossible to get lost on the approximately 40 minute hike down to the beach area. There are also great views of the Reservoir to the right as you hike down.
When you arrive into the village, stay on the same path and keep walking into the main village area. On the left is the Surf Hong Kong building. Someone can meet you there. Phone signal is restored for many by this point.