Below is a simple example. There is more power in this function when you use the breaking order (ie orders the items regardless of their position/location in the hierarchy).
WITH
SET SampleSet AS '{[Customers].[All Customers].[USA].[USA].CHILDREN}'
SELECT
Order(SampleSet, [Store Sales], ASC) ON 1,
{[Measures].[Store Sales]} ON 0
FROM
[Sales]