Sims 2 Castaway Mobile Help! How to go to the 2nd island from the 1st island?

I have install Sims 2 Castaway game on my handphone as i would like to try it out. At first, i managed to get all the goals done in the 1st island & eventually build a raft there. After a while, i heard that there was a 2nd island to explore but I'm struck at the 1st island & did not know how to get there. So, i really would like someone to tell me how to get there, please? thanks a lot!