Extend README with better instructions for how to perform OTA via cloud server

Author: aentinger

extras/tools/README.md

@@ -1,5 +1,27 @@
-`bin2ota.py`
-============
+Firmware Over-The-Air Tools
+===========================
+
+## How-to-prepare obtain a binary for OTA
+
+1) In the IDE do `Sketch` -> `Export compiled Binary`
+2) Copy the compiled binary `sketch.bin` in `ArduinoIoTCloud/extras/tools/`
+```bash
+cp sketch.bin ~/Arduino/libraries/ArduinoIoTCloud/extras/tools/
+```
+3) Add the length and CRC
+```bash
+./bin2ota.py sketch.bin sketch.ota
+```
+4) Convert to JSON
+```bash
+./bin2json.py sketch.ota sketch.json
+```
+5) Upload to Arduino IoT Cloud Server
+```bash
+./ota-upload.sh CLIENT_ID CLIENT_SECRET DEVICE_ID sketch.json
+```
+
+## `bin2ota.py`
 This tool can be used to extend (actually prefix) a binary generated with e.g. the Arduino IDE with the required length and crc values required to perform an OTA (Over-The-Air) update of the firmware.
 
 ### How-To-Use
@@ -25,17 +47,15 @@ This tool can be used to extend (actually prefix) a binary generated with e.g. t
 0000030   0000 0000 7485 0000 0000 0000 0000 0000
 ```
 
-`bin2json.py`
-=============
+## `bin2json.py`
 This tool converts the binary file into base64 encoded JSON which is necessary for feeding it to the server.
 
 ### How-To-Use
 ```bash
 ./bin2json.py sketch.ota sketch.json
 ```
 
-`ota-upload.sh`
-==============
+## `ota-upload.sh`
 This tool allows to upload a OTA binary to a device via a Arduino cloud server.
 
 ### How-To-Use