use CGI qw(-oldstyle_urls);
my $q = new CGI;
# ...
if ($q->param('last')) {
        last_page($q);
} else {
        next_page($q);
}

sub next_page {
        # ...
        $url = $q->url('-query' => 1);
        $last = ($url =~ /\?/) ? '&last=1' : '?last=1';

        # Here is the delay, 10 seconds
        print $q->header('-Refresh' => "10;URL=$url$last"),
        # print the rest of the 1st page here...
}

sub last_page {
        # ...
        print $q->header(),
        # etc...
}