defining PWM on different GPIO on zephyr based project

Hi,

I am new in Device tree concept. I am trying to operate a buzzer via PWM.

In our board, the buzzer is connected in GPIO 3.

I changed a segment in file nrf52dk_nrf52832-pinctrl.dtsi as follow:

( port changed from 17 to 3)

pwm0_default: pwm0_default {
group1 {
psels = <NRF_PSEL(PWM_OUT0, 0, 3)>;
nordic,invert;
};
};

pwm0_sleep: pwm0_sleep {
group1 {
psels = <NRF_PSEL(PWM_OUT0, 0, 3)>;
low-power-enable;

};
};

The buzzer make a beep sound using this code:

static const struct pwm_dt_spec pwm_led0 = PWM_DT_SPEC_GET(DT_ALIAS(pwm_led0));
ret = pwm_set_dt(&pwm_led0, period, period/2);
I know its not the correct way to change the board dtsi files... 

1) Can you send me an overlay file for buzzer setting the port 3 ?

2) I also can't understand how/where to attach this overlay file ... ?

unrelated issue

3)  I am trying to stop the buzzer using 

    ret = pwm_set_dt(&pwm_led0, 0, 0);
or
    pwm_set_pulse_dt(&pwm_led0, 0);
the buzzer stops, but I still hear very weak humming sound and I notice a high current consumption.
How can I fix this problem ?
Alon