I don't know if there is a manual for it but I have changed my own oil and getting ready to change again. oil ring is very easy. It has a spot which is very visible. Simply slide the old oil ring out and roll the new one to its place (you will see the oil ring's place when you look at the filter) Very easy, trust me. Look at the old oil filter and see where the oil ring is and copy it.

You probably already know this but I will type a step by step instructions anyways.

-Lift the car up (level lift would be great)
-Remove the cover at the bottom of the car
-Unscrew the oil drain plug, let it drain till it is barely dripping
-While the oil is draining, unscrew the oilfilter (located at the top of the engine) Place the new oil ring to the new oil filter, screw it back into the engine. (Hand tight is good enough)
-Once the oil is fully drained, screw the bolt back on
-Remove the oil cap from the top of the engine
-Use a funnel and pour 8,5 qrts of oil in
-Before dropping the car, start the engine, look at the bottom of the engine to see if there is any oil leak from the drain plug. If there isn't (if you tightened it enough, there wont be any leaks, but check it just to make sure)
-Put the cover back on
-Drop the car.

You are all set.