or download this
my $TextBox = $slide->Shapes->AddTextbox({
Orientation => 1, Left => 5, Top => 5,
...
$TextBox->TextFrame->TextRange->{Text} ="Big Ole Test";
$TextBox->{'Fill'}{'BackColor'}{'RGB'} = 255; # 0000ff BlueGreenRed;
$TextBox->{'Fill'}->Solid;