To get set up you will need an Eight Smart Mattress or Sleep Tracker. https://eightsleep.com
Once you have set up your Eight, find the Eight skill in the Amazon Alexa app. When you click to "Enable Skill" you will be asked to enter your Eight username and password to link the accounts.
You are now able to communicate with Eight. Tell Alexa to ask Eight how you slept last night, or to control the warming of your bed!
Note: If your partner wants to get their sleep information from Alexa they will need to share their sleep metrics with the main Eight account you used to link to Alexa. Go to the Eight app and make sure the partner account shares their data with the main account.