Hello Ken,
I apologize for any troubles you might have had experienced.
To answer your question, the sequence from underneath should be gasket, washer and then retaining ring.  That way you can really torque the retaining ring enabling you to also tighten the bolts if required , additionally the bolts will not break the gasket.
Should you have any other questions please send a message to customer.service@conglom.com
-Customer Service