Added note for serial port

ESP32/README.md

@@ -28,6 +28,7 @@ You will see the ESP-IDF configuration interface.
 
 - Go to `Azure IoT Central Configuration` and fill in the Azure IoT device credentials from earlier, as well as your Wi-Fi SSID and Password
 - Go to `Serial flasher config` to configure specify the serial port to which your device is connected
+  - *Note: If you are using the Linux subsystem on Windows, the serial port will be `/dev/ttySN`, where **N** is the number of the `COM` port. For example, if your device is connected to `COM5`, the serial port will be `/dev/tty/S5`.
 
 ### Building and flashing to the ESP device.
 
@@ -64,4 +65,4 @@ To exit the monitor, hit Control-]
 See [esp-azure/main/azure-iot-central.c](./esp-azure/main/azure-iot-central.c) for IoTCentral specific connection and telemetry codes.
 If you want to learn more advanced functionality, visit [../MXCHIP/mxchip_advanced/src/AzureIOTClient.cpp](../MXCHIP/mxchip_advanced/src/AzureIOTClient.cpp)
 
-Both projects use `iotc` wrapper. You can use the IoTCentral related logic interchangebly on both side.
+Both projects use `iotc` wrapper. You can use the IoTCentral related logic interchangebly on both side.