How do I separate interface and implementation cleanly for embedded systems?

#ifndef LED_H
#define LED_H

class LED {
public:
    LED(int pin);
    void turnOn();
    void turnOff();
    
private:
    int pin;
};

#endif // LED_H

// LED.cpp
#include "LED.h"
#include 

LED::LED(int pin) : pin(pin) {
    pinMode(pin, OUTPUT);
}

void LED::turnOn() {
    digitalWrite(pin, HIGH);
}

void LED::turnOff() {
    digitalWrite(pin, LOW);
}