Cleared Interview

[babyface]

Hi,
I had an interview and the officer accepted my application. I have been asked to get authorization (ARC) to enter Canada (I was deported for overstaying)

Along with the form I have to send a letter explaining the reason for my overstay. Can someone help me in composing this letter. Please tell me how to write this letter, I mean how do I compose it.

Thank you for your help!