exhaust leak, donut gasket? manifold gasket? repair procedure on 1996 Cadillac DeVille

I have a leaky gasket not sure if it is the manifold or a donut gasket. Need a repair procedure for both types.

Asked by for the 1996 Cadillac DeVille
If you need a procedure try www.alldatadiy.com there is a lot of information, but there is a fee for the use of it.
Thank you for the response
U Bet and good luck.