Max your sunsingers agility, use right rock strategy and make sure you get a titan or someone to distract boomers. When you're on the rock and ready, call out to your team to fire rockets and jump up on the platform before crota kneels. If it is your first time swordbearing at all, just get 6 hits on crota each sword, (3 every time you go up). Once you're comfortable and better with the sword, you can try getting in 7 hits. Also use apotheosis veil and red death to regenerate health when you need it. Flame shield comes in handy. Good luck!