Hi,
An example of using the FSCI protocol is the ble_fsci_black_box. As a start point please consider Kinetis FSCI Host Application Programming Interface.pdf , chapter 9.8. BLE heart rate service use case. (sdk folder -> ..\docs\wireless\Thread/).
The python file contains an equivalent list of commands that can also be sent from TestTool ->CommandLine -> BLE xml commands set.
An example of accessing GAP commands from TestTool is below.

As a note, please consider that the FSCI functionality is enabled by default on the following examples:
- ble_fsci_black_box
- otap_server - required for Over the air programming server implementation.
Regards,
Ovidiu