for this one you only need 1 unit hestati, one unit archers, and one unit calvery per phalanx
set it up like this
p a
h
c
enage the hestati and order the archers to fire into the side of the phalanx,
while this is happening swing your calvary behind the phalanx and drive the calvery into the back of it.
disengage the hestati and calvery and let the archers finish up from a safe distance.
*this should only be attempted when the enemy is defending a hilltop*
I'm a lumberjack and I'm okay....