I need some php help...and then some

Ok, heres the deal and I'll try to be as specific as I can. I doing some webdesign right now and I've undertaken a project that I'm a bit incapable of at the moment. the site that I am working on requires me to setup a mySql database with relatively simple information product_id, product_description, cost and perhaps a few others. what I need is an interface that is orderform like in functionality with the exception that when someone enters a product number the rest of the form is populated with the data pertaining to the product number and then after the form is populated with all of the particular items a person is ordering it can be emailed to the company (that part I'm ok with) I'm certain that it is entirely feasible, I just don't know how and where to start. I'm currently in the very early stages of learning php ...if only I had more time or programming experience...but none the less if anyone has any ideas or suggestions I certainly would appreciate it. Regards, J.