top and second ring should be of different color; top is usually a lighter color...
BUT much more important than color is SHAPE!
the top ring has a rounded shape (the face that's against the cylinder wall is rounded that is

)
the second ring is asymmetrical; the lower edge is ever so slightly wider than the upper.
(it has distinct sharp corners though compared to the top ring!)
both (top and second) should have a marking on the top.
likely A (top) and B (second) sometimes A is just marked with a T though indicating the top ring
(as it's symmetrical it shouldn't matter which way around it's installed other than for good practice)
the oil rings are AFAIK identical to one another and it makes no difference as to which one is the upper and which is the lower
and IIRC it doesn't even matter in which orientation they're installed.
'sid