Updated Porting to non Arduino Platforms (markdown)

Porting-to-non-Arduino-Platforms.md

@@ -21,4 +21,19 @@ void wrap_HAL_GPIO_WritePin(uint32_t pin, GPIO_PinState value) {
 }
 ```
 
-This has to be done for all Arduino functions listed on the page [Custom Build Configuration](https://github.com/jgromes/RadioLib/wiki/Custom-Build-Configuration).
+This has to be done for all Arduino functions listed on the page [Custom Build Configuration](https://github.com/jgromes/RadioLib/wiki/Custom-Build-Configuration).
+
+Once done, the last thing left to do is to initialize all callbacks defined in the `noarduino.h` file. The callbacks themselves are generated by RadioLib - the user only has to call the initalizing functions:
+
+```c++
+SX1278 radio = new Module(1, 2, 3, 4);
+
+(...)
+radio.setCb_digitalRead(::wrap_HAL_GPIO_ReadPin);
+radio.setCb_digitalWrite(::wrap_HAL_GPIO_WritePin);
+// etc. for all the callbacks
+(...)
+
+// we can go now!
+radio.begin();
+```