If you want Nick to consider playing your original music you must send him an email with your music file as an attachment. If you have a website include that in the email as it will be mentioned and linked to on the website.
The email address is email@example.com
The music must have been written and played by you.
The music file must be an mp3 or mp4a and have your name and the title of the piece of music as the file name
eg. Nick Tann-Dont Make Me Wait.mp3
If Nick plays your music he will email you to let you know.
This video shows you how to make an MP3 file using iTunes