What do you mean by code for Storing on the FileSystem? You need to have the files in the filesystem directory.If you have to create the files programatically then you can use FileStream to create and write the data to the files. You should have the binary data which you read from the file earlier.
To display the files, display the filename in a LinkButton on your page and use the below code in the LinkButton1_Click event to download the file to the clients machine.
//ContentType should be changed based on the file type
Response.ContentType = "image/jpeg";
Response.AppendHeader("Content-Disposition","attachment; filename=filenamewithpath");
Response.TransmitFile( Server.MapPath("filenamerelativepath") );
Response.End();