add your own music on iTunes store

If you mean sell your music in the store : http://www.apple.com/itunes/working-itunes/sell-content/music-faq.html

If you mean have your own music available in the cloud so that you can download/stream it on your devices/computers without needing to sync/copy it : http://www.apple.com/itunes/itunes-match/

would you be able to tell me how too

See the link in my above reply