open INPUT, "<./input.txt"; # assuming that's your input
open OUTPUT, ">./output.csv"; # comma-separated-values output
print OUTPUT "First column heading,Second column heading,Third column heading\n";
while (<INPUT>) {
  my $first = s/(\d+)\.+//;
  my @others = split /\s\+/;
  print OUTPUT join(',' ($first, @others)).$/;
}