Anthony Bouchard, writing for iDownloadBlog:

To access Emergency SOS, all you need to do is press and hold the side button on your Apple Watch, and you’ll see a new red “SOS” slider at the bottom of the slider list. Sliding this slider initiates a 911 call and fires off text messages to your emergency contacts within seconds.

But there’s more to it than that. Read the article and learn about auto-call and how to set up your emergency contacts.