spindle setup

I want to connect my spindle to a 5 Axis Breakout Board Interface Adapter via a raspberry pi5. I can control the stepper motors (XYZ). I just can't control the spindle. Is there an example for the HAL file?

If I bypass the relay contact. Then the spindle will rotate to the maximum. If I press the + button it slows down. When I press the - button it speeds up. When I press the stop button, it starts running at maximum speed. 
Anyone have a solution?

Greetings Philip

Invert the spindle pin in hal.
something like
setp rpi_pin_number_00 invert true

Thank you. I'm going to test that tomorrow.

And how can I operate the relays of the 5 Axis CNC Breakout Board.

Greetings Philip