You need to put the spreadsheet somewhere that is publically accessible. Also, spreadsheet are not a web development issue, so I don't know whether anyone will be able to help. Why did you choose the PHP section? I'm struggling to work out where the thread belongs...
Anyway, the PHP syntax for concatenating variables is '.', e.g.
$concat=$col1.' '.$col2.' '.$col3;
Though I'm not sure whether that is any help to you, as I have no idea how you would interface that to the spreadsheet!!!