I know how to insert it to the end by:
$arr[] = $item;
But how to insert it to the beginning?
Use array_unshift($array, $item);
$arr = array('item2', 'item3', 'item4');
array_unshift($arr , 'item1');
print_r($arr);
will give you
Array
(
[0] => item1
[1] => item2
[2] => item3
[3] => item4
)