Train to Wanning from Sanya

I have booked a hotel at Dadonghai. After my stay, I want to take the train to Wanning. My questions are:

(a) Where is the train station and what bus should I take from Dadonghai to the train station?
(b) What is the cost of the train ticket to Wanning and what is the schedule like? Where is the train station at Wanning?