High Power H-Bridge with IR2125 Drivers Problem
Vss must be grounded. With your current configuration, neither Q5 nor Q6 can conduct current, since their source leads only connect to the IR2125.

And controlling motor direction is easy. For one direction, keep HA and LB low, HB high, and apply your PWM to LA. For the other direction, keep LA and HB low, HA high, and apply PWM to LB.

And, for what it's worth, I really doubt that your gate resistors (R6 - R9) need to be 1 watt units. Not at 30 kHz.