From the synopsis

 use Net::HTTP;
 my $s = Net::HTTP->new(Host => "www.perl.com") || die $@;
 $s->write_request(GET => "/", 'User-Agent' => "Mozilla/5.0");
 my($code, $mess, %h) = $s->read_response_headers;

 while (1) {
    my $buf;
    my $n = $s->read_entity_body($buf, 1024);
    die "read failed: $!" unless defined $n;
    last unless $n;
    print $buf;
 }
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That read_entity_body part is what actually reads the file content.

I think its a better idea if you use WWW::Mechanize, its a higher level interface

use WWW::Mechanize;
my $ua=WWW::Mechanize->new();
$ua->get($url);
$ua->save_content('filename.html') if $ua->success();
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