Install the Spreadsheet::ParseExcel module. Import the Spreadsheet::ParseExcel and Spreadsheet::ParseExcel::SaveParser modules into your Perl script.

use Spreadsheet::ParseExcel;
use Spreadsheet::ParseExcel::SaveParser;

These two lines are used to define the spreadsheet that contains the data (orignal.xls in this example).

my $parser   = new Spreadsheet::ParseExcel::SaveParser;
my $original = $parser->Parse('original.xls');

These variables are used so that you are starting at cell A1 in the first sheet in the spreadsheet.

my $sheet = 0;
my $row   = 0;
my $col   = 0;

This gets the format of the data in the spreadsheet (bold italic underline font et cetera) so that you do not lose the format of the spreadsheet.

my $format   = $template->{Worksheet}[$sheet]
                        ->{Cells}[$row][$col]
                        ->{FormatNo};

This replaces certain cells with the text "Hello World".

# Updates row 0 column 0 (cell A1) with the text Hello World
$original->AddCell(0, 0, 0, 'Hello World', $format);

# Updates row 0 column 1 (cell B1) with the text Hello World
$original->AddCell(0, 0, 1, 'Hello World', $format);

# Updates row 1 column 0 (cell A2) with the text Hello World
$original->AddCell(0, 1, 0, 'Hello World', $format);

This creates a new spreadsheet, most appropriately named new.xls.

my $workbook;

{
  local $^W = 0;
  $workbook = $template->SaveAs('new.xls');
}