When your alarm goes off, the Yeelights will blink a few times.
When your alarm goes off on your Alexa device, the Yeelights will blink a few times. In order to set the lights you need to open YeelightApp, go to Scene, add '+' button, then select your bulb/s. Select from favourites, then select the bottom one, 'Flash Notify'. Then give the Scene a name, go back to the IFTTT rule and select your Scene.