Stage 1: Cannon Islet
There are a total of 8 cannons, 4 at the front, 4 at the back.
it is recommended that mages and archers man the 4 cannons at the back. Clerics and warriors handle the ones at the front.
There will be 5 waves of monsters coming from the cave in front.
Everyone just keep shooting at whatever that are coming out from the cave.
The 1st and 2nd waves of monster are very easy and normally won't pose any troubles
Priest: At the 3rd, 4th and 5th wave, if required, priest should cast Hand of Miracle in the middle of the 8 cannons to protect anyone from damage.
Warrior: Highland the party member if required.
Force User: Time acceleration if needed so that the priest can cast miracle hand at 5th wave.
Paladin: Provoke and distract monsters below the cannon. Keep yourself alive with various invincible and block skills.
See full guide here