the Monarco HAT has hardware PWM and therefore does not need to create PWM in software using a PWM block. Documentation to the PWM on Monarco HAT can be found on page 16 in Monarco technical specification https://www.monarco.io/docs/Monarco-HAT-Hardware-Reference-Manual.pdf.
All you need to do is set the PWM frequency (in your case to 50 Hz) and calculate the actual duty cycle for one channel according to the equation:
Duty_cycle = pulse_width/period_length
Take a look at example 0121-05_Monarco_HAT_PWM_output to find out how to set the frequency and duty cycle for PWM1 (for example).
Hope, this will be helpfull.