error convert int to const char

Northof49:
Invalid conversion from int to const char is what it says, and highlights that line.

The error is in the following section:

void joystickJoystickMoveRightCallback(int value) {
  /* Start your code (joystickJoystickMoveRightCallback) */
  
  steerServoPos = map(atoi(value), 0, 1023, 90, 180); 

  /* End your code */
}

you're calling atoi on a value that is already defined as an integer. Hence the error.

Hope this helps,

Brad
KF7FER