Referring to the CGI documentation, the following example is presented.

$cookie = $query->cookie(-name=>'sessionID',
                             -value=>'xyzzy',
                             -expires=>'+1h',
                             -path=>'/cgi-bin/database',
                             -domain=>'.capricorn.org',
                             -secure=>1);
    print $query->header(-cookie=>$cookie);
[download]

I would recommend that you read the pod for CGIand use the code presented there. As a pointer, I would stick to the CGI module and not use CGI::Cookie. I say this as I've had no end of problems with CGI::Cookie in the past that disappeared once CGI was used instead.

Note that the code example assumes you have already created a CGI query object.

Hope that helps.