The first 2 bosses in UP are really easy. Do them on normal (you'll still get rep) to get the hang of it. First boss, when she sacrifices run your team up and drop magmas and do an aoe with your druid (nothing to tank during this phase) then run back to the floor and start dps'ing the boss again. Rinse and repeat.

Second boss keep up cleansing and you must be able to cast heals on each party member because the final boss spears randomly. A riptide usually covers it.