File transfer problems

Question

My problem is this. I want to download a file from the webbserver and save it to a local client. And i the work flow is like this. After the user has register his customer data, he reicive an email with a link to the file on the server and then the dowload starts. I don´t have any idea of how to do this :-( Could anyone give me some idea´s or example of how to do this or some other way to do this Sorry for my poor english