$ perl -Mstrict -Mwarnings -le '
    use Data::Dumper;

    # Declare an empty array (Note: no "splice" required)
    my @records;

    # Initialise the array with 2 elements
    #  Each element must be a scalar
    #  If an element is an array of values, you need an arrayref
    @records = ( [ "A", 1, 2, 3 ], [ "B", 4, 5, 6 ] );
    print "\$records[1][2]: ", $records[1][2];

    # Push another array of values (as an arrayref)
    push @records, [ "C", 7, 8, 9 ];
    print "\$records[2][2]: ",  $records[2][2];

    # "join" creates a string (strings are scalar values)
    push @records, join ",", "D", 10, 11, 12;
    print "\$records[3]: ", $records[3];

    # Add a hash (as a hashref - which is also a scalar value)
    push @records, { E => 13, F => 14, G => 15 };
    print "\$records[4]{G}: ", $records[4]{G};

    # The entire data structure:
    print Dumper \@records;
'
$records[1][2]: 5
$records[2][2]: 8
$records[3]: D,10,11,12
$records[4]{G}: 15
$VAR1 = [
          [
            'A',
            1,
            2,
            3
          ],
          [
            'B',
            4,
            5,
            6
          ],
          [
            'C',
            7,
            8,
            9
          ],
          'D,10,11,12',
          {
            'G' => 15,
            'F' => 14,
            'E' => 13
          }
        ];