Hi Alex,
You can take as reference the Bluetooth® Low Energy Demo Applications User’s Guide
Chapter 5.17.3 Usage with test tool for Connectivity products
It describes the process for the test tool, you can take as reference the commands that the tool uses.
Also, a better reference the Framework Serial Communication Interface (FSCI) for Bluetooth® Low Energy (BLE) Host Stack will help you with your app implementation.
Best Regards,
Mario