By default your domain's DNS will be automatically updated to connect to Rebel Cloud Email. If the domain does not connect automatically, or if you need to set up your DNS elsewhere, you can follow this guide to find the DNS records you will need.
Login to your Rebel account. Then go to your Email Manager by clicking Email Manager in the left hand menu, or in the My Account menu on the top right hand side of your screen.
Click on Options to the right of your Rebel Cloud Email package, then click DNS Settings.
This page will display the 4 MX records, and the 1 TXT record you will need to enter to let you send and receive email through your domain.