From Managua, take a bus to Rivas (can be taken from mercado Roberto Huembes) From Rivas take a taxi to San Jorge. From San Jorge, take a ferry to the island. Once in the island you have several options: ranging from a chicken bus to a shuttle from the port. (Say you are going to huellas hostel) We are located in El Madroñal next to Pizzeria Mediterranea. Have a nice trip :)