Hi @ranaelbastawisy, unfortunately, we do not provide any samples that explicitly show how to implement NPS at this time.
Non-Player Characters responding to receive gaze signals is simply a concept whereby you can increase the immersion of a player within a game and control the NPS reaction according to dwell time, etc. However, the actual coding part is simply a matter of mapping to an object so that upon receiving gaze from the user, actions will be triggered.
The syntax for this is covered in the Unity Sample documentation at it’s most basic level @ https://vr.tobii.com/sdk/develop/unity/getting-started/vive-pro-eye/#step-7-create-a-cube-and-place-it-somewhere-in-the-scene
with more sophisticated mapping in the “object mapping” section of the Unity Samples page. Apologies for any inconvenience, hopefully this is enough to get you started.