Here's how to add / create an email account from within cPanel:
1) Log in to cPanel
2) Click on "Email Accounts"
3) Click "Create"
4) Enter the mailbox details as per your preference (make a note of the password you specify, this can't be seen at a later date), then click "Create" at the bottom of the page.
5) You'll now be able to see the mailbox you've created at the bottom of the page. On the same line as the mailbox is a "Connect devices" button that can be clicked to obtain the settings you'd need to enter in to a mail client to connect it to the mailbox you've created.