This is a H-Bridge motor driver. It uses IR2104 mosfet drivers, one 7812 to power mosfet drivers and 4 mosfets to control the motor. 4 mosfets can control the motor direction and brake. IR2104 controls one high side and one low side mosfet. When one High side and one Low side mosfet starts to conduct motor starts to turn and when other 2 mosfets conduct motor starts to turn the opposite way. When two low side mosfets are conducting motor can brake safely. This logic is easly implemented on the board with the logic of IR2104 which makes it impossible to create a short circuit between mosfets.

To use the module first power the module with the power source that you are trying to drive the motor with, then you have to apply 5v to both S1 and S2, and apply a pwm signal to p1 or p2. Don't forget to connect the ground pin of the microcontroller to the ground pin. You can use the 12V out to power an arduino board or something similar via VİN pin. To brake you have to stop applying pwm signals to the module and the motor will brake. Module should be able to handle 15-20 amps. Have Fun!

Use this PCB at your own risk !

I have tested the module without a pcb and it worked flawlessly, so there is no problem with the schematic.