If xou want to go to Indonesia, this is where you start from. Make sure you have made reservations before: you can find the different ferry companies on Internet(I took Penguin). Be there an hour before, because you need to go through passport control and customs. To get there: take the MRT to Tanah Merah. From there, either take bus 35 or a cab. Remember that coming back is not so smooth: ferries from Indonesia are typically late, and upon arrival the bus is just gone, so all you can do is queue with the others for the occasional cab!