When you create a non-clustered index on a table, it is a pointer to the clustered index, if one exists. However if one does not, then the data in the table will be ordered by the non_clustered index. The only way I can think to illustrate this to have two indexes on the table, and show the query order by having them both be unclustered, and then make one clustered, and then make the other clustered (note you can only have one clustered index):
CREATE TABLE test_table (ID tinyint, ID2 tinyint);
GO
---CREATE NONCLUSTERED INDEX non_clustered_Indexa
CREATE INDEX non_clustered_Indexa
ON test_table (ID);
--CREATE NONCLUSTERED INDEX non_clustered_Indexb
CREATE INDEX non_clustered_Indexb
ON test_table (ID2);
INSERT INTO test_table VALUES (2, 1);
INSERT INTO test_table VALUES (1, 2);
INSERT INTO test_table VALUES (3, 3);
GO
SELECT * FROM test_table;
GO