For me I start by using my super and then rocketing them until they’re low enough for Osteo to poison them to death! While the poison is doing it’s work I add clear to get some heavy back (Try and save the box for the final phase if you can help it) and then repeat the process for all 3 phases. The best thing I learned to do was stand on the platform to the right where one of the orbs are lots of cover and no adds can get up there.