If your mail is stored in a file and the mail command does not open it automatically then you might need to specify the file to open:
bash$ mail -f /home/bob/mbox
Once you have mail open you will see a list of subjects and numbers. You can type the number of the message to view it. Once you have read the message you can press q to quit, n for your next message, d to delete, or ? to see your available options. When you exit mail will usually store the messages you read in your home directory in a file called mbox. To send mail type:
bash$ mail email@example.com Subject:
At the subject prompt type the subject in and press Enter. Then type your message until you have finished. Once you are done you can press either Ctrl-d or . on a line by itself to finish. Then you can add in the other people you want to carbon-copy the email message to.