Could you give a more deep explanation?

public int[] WiggleSort(int[] array)
{
_array = array;
int median = findKThLargest(_array.Length / 2);
int left = 0, i = 0, right = _array.Length - 1;
while (i <= right)
{
if (_array[newIndex(i)] > median)
{
//put newIndex(i) at odd index(from 1, 3, to 5, ...)
swap(newIndex(left++), newIndex(i));
i++;
}
else if (_array[newIndex(i)] < median)
{
//put newIndex(i) at even index(max even index to little .... )
swap(newIndex(right--), newIndex(i)); //right--, so i relatively toward right 1 step
}
else
{
i++;
}
}
return _array;
}