multi dimensional arrays [resolved]

[Acidic]

I know this might seem easy, but I have been looking and either can't find what I'm looking for or I find something that looks very complex.

Firstly how do you define an array, I PHP is typeless, but in JavaScript I always define arrays out of habit, and I would like to keep up the habit.

secondly, how do you make a multiD one?

I thought it would be:
$a = new array();
//or new array($a);
then:
$a[0] = ["1","2"];
$a[1] = ["3","4"];
etc.

I get errors though.
Someone please help.