Log in to your personal Mailinblack area and go to Access my admin area at the top right of your screen by clicking on your Surname and First name.
From your admin area, click the Domains menu on the left.
Click on Add a domain and fill in your domain name, as well as the corresponding target server to which the emails will be sent (the smallest MX in your domain host). You have 2 possibilities:
saisissez votre numéro de téléphone