What exactly are you having trouble with? I would expect the Duty Finder to match you with 7 other players who outgear Cape Westwind so much that they could complete it with only half the party.

As a new PLD with weaker gear, it would probably be easiest if you went with Sword Oath up attacking the main boss, but checking behind you for the adds that spawn later. When they show up, switch to Shield Oath and try to pick up as many of them as you can. Use Provoke to grab any that you can't easily get hate on, and use defensive abilities once you have them on you. Also, at that point stay out of the fire and away from the boss. You may not be able to get any enemies to focus on you if some of the players you're matched with have better L50 gear or are >L50.