Quest Sea Dragon, Blocked

Hi guys! I'm new in this forum, ty for the instruction for download and play to ssonline!

I have problem from the beginning, with a quest for the "Sea Dragon" Class...

After the first 3/4 mini quest, the Siren give me a quest, where appear the "Poseidon Trident". I must commune with him, and after, appear an evocation of Sea Dragon, but i don't understand what should i do! I try to attack but he have too much of life, and if he attack me, give me a KO and disappear. If i waiting, after a bit of second the evocation disappear. So this quest i don't understand how to complete and go forwrd in the game!

Sry for but i'm very noob in this game, and chinese language doesn't help me!! :D

Ty all! See ya in game!

The problem is you are so weak and you can't beat the boss so you must be stronger or add someone to party for help you o.o

Ty for reply! But i found the ask in the post on Sea Dragon Class Discussion! ;)