Adding an API key to Sansheets is very simple. But there is two things you need to do first: Getting Sansheets ready and creating an API key. In case those are already done you can continue adding that API key to Sansheets.
You will find the option to add an API key in the 'Add-ons' menu under 'Santiment Data':
A popup will open asking you for your API key:
Copy it from the Sanbase account settings and paste it here, then click 'Ok'.
Sansheets will now confirm that you entered a valid API key:
You will now have access to more data, depending on your stake of SAN tokens.