I am a newbie, apology for posting again if there is similar thread already exists (posting question coz I didn't find one).

I am learning how to setup an exchange. As of now I know how to send and receive the bit coins to and from address. I have sample code with me which works fine.

But now am stuck at point how to buy and sell the bitcoins?
Any help (article/blog/book to read, video tutorial, existing thread link, hints) would be much appreciated.

Thanks in advance.