e-shop problem

Hi I'm designing internet shop based on PHP and MySQL, but I don't know how to solve the following problem: when the customer want to buy some article he/she click check button and the article is in her/his bag. So the problem is I'm not familiar with this technology. Could anyone explain me how this things works. Or maybe you know some good place (in internet) where thing like this are explained from basis. Thanks for all help Regards Andrzej W ------------------------------------ e-mail: alfwro@wp.pl http://republika.pl/wroblewski_online