Purchasing Sindo ferry tickets through Traveloka is very easy. In HarbourFront there are some points you need to follow. First, go to Sindo office on level 3 to exchange your e-ticket with a boarding pass. Then go down to level 2 to the waiting room, there is a baggage storage facility (should you need it) on one end of the waiting room. Down there, there are two paths each leading to different boarding gate, unfortunately there is no clear signage which one to follow. You should take the path next to the baggage storage facility, to clear immigration and other formalities. Sindo ferries have double decker cabins, I chose the upper level to get better view. Bottled drink water is available and you can take it by yourself as they do not distribute it. The journey to Batam Centre Ferry Terminal itself was punctual and safe. Thank you Sindo Ferry.