Register the connection details for your source and target instances using the following command. For example, if you're synchronizing content for a test to production deployment, you might have development (DEV), staging (TEST), and production (PROD) instances.

cec register-server DEV -e http://server:port -u username -p password
cec register-server TEST -e http://server:port -u username -p password
cec register-server PROD -e http://server:port -u username -p password

• The first value (for example, DEV, TEST, PROD) is the server name used to identify the instance endpoint. This value can be any name you choose.
• The -e value is the server and port that make up the URL you use to access the instance.
• The -u value is the username. This user must be the user who can access the sites and assets on the source instance or who will own the sites and assets on the target instance.
• The -p value is the password for the user.