Before you can make a backup of a database, you first need to SSH into the server.
If you are not familiar with the login command line, it is:
ssh -p <portnumber> ‘user’@servername.com
Once logged in, enter the following command, replacing DATABASE_NAME with the name of your database. This will generate your backup, which will be called BACKUP.sql.
mysqldump DATABASE_NAME > BACKUP.sql