1. How does the Google sheets add-on work
The Saleslift Google sheets add-on gives the business email address by analyzing the first name, last name and the domain of a contact. You need to provide the email address which is used for signing up with Saleslift and the API token. The add-on can be installed from here.
2. Where can I find the API token?
The API token for your account can be accessed from here.