Activate Alexa scene

How do I activate a scene from alexa from motion sensor, I can not select it from options…

Currently it is not possible to activate an Alexa scene from the Hue motion sensor. You will need to create a scene on your Hue bridge, and then you can use it on the motion sensor.

A Hue bridge cannot send commands to Alexa (or any other external device) when motion is detected, Philips Hue would need to add support for this first.