Place auras , buffbeam, reflective walls and as many owls as you can during first buildphase. Build the remaining owls during first wave.
Place your upgrader at hint 2 aiming at hint 3 during first and second wave. Hint 2 is on the right side on top of the bridge.
When fully upgraded bring in your TB Monk and Summoners with Monk/Huntress guardians as you need and hide under the bridge for the remaining waves and until boss(es) is/are dead during bosswave.
Note: depending on your aura Monks range you may need to play around a bit with the aura placement