Make sure the default location the Haven app is set to the location you wish to have Alexa support.
Go to the home screen of the Alexa app. Scroll down to where it says "Popular Skills" and tap "Browse Skills." From there tap the search icon at the top right of the screen and search for "Haven Lights". Tap Haven Lights from the results.
Tap "Enable to Use."
Tap "Link Account" and log in using your Haven Lighting account. (Use the same login info you use on the Haven app.)