Does the believer have one nature or two?

Have you ever found the ideas and concepts of the old and new nature of Christians confusing.

• Do we have one nature or two?
• What is the old nature and what is the new nature?
• Who is this 'old man' that Paul talks about?
• What is the 'new man' referring to?
• What is the 'flesh' and how does it work in me?
• Aren't we a new creation?

I found the article found at this link very helpful: Does the Believer Have One Nature or Two?

There are still some questions I have, but this article cleared a lot of them up for me. Take a look at it!