Can I use both address as separate accounts?

They are both tied to your existing iCloud account. You can send email from either address, and you can choose either as your default address when composing new email (both of these are covered in the article you were viewing here: http://support.apple.com/kb/HT5441), but email sent to either address comes to the same inbox.

No. It's only a seperate email address feeding into the same email account - not a seperate email account.