What you have here is a hash (indexed by form name), containing arrays of hashes. You can loop on the main hash, pulling out the specified fields from each hash in the array. For example:

while (my ($formname, $formarray) = each %data) {
    print $formname, "\n";

    foreach (@$formarray) {
        print "  type:       ", $_->{type},       "\n";
        print "  field_name: ", $_->{field_name}, "\n";
        print "  value:      ", $_->{value},      "\n";
    }
}

Note: as broquaint mentioned, you should see perlreftut. I also find perldsc quite helpful at times.