So...first thing you'll want to do is to run the boat for a little bit. The manual says 5 minutes or more. I don't recommend the "more" part, you just wanna warm up the oil, not heat it all up.
Next thing to do is remove the dipstick and set it aside. Take the hose from the oil extractor and put it down the dipstick tube until it bottoms out; shake it around a bit to make sure it just isn't hung up on something and that it's truly at the bottom. Follow the instructions for your oil extractor and start the process of removing the oil from the dipstick tube - this is the FIRST extraction point.
Take your oil filter removal tool of choice, and loosen the filter. Spin the filter 360 degrees, no more. Let it sit and drain. The manual offers a tip for filter removal - punch a hole in the top of the oil filter using a nail or the like so the filter can breathe and drain the majority of oil inside of it into the engine.
I do NOT recommend that you do this. If you wish to punch a hole in the top of the filter with a nail, DO NOT do it dead center of the filter. Do it off center - the pickup tube is right in the center, I'd hate to see someone damage their engine doing something as simple as an oil change, that's why my recommendation to NOT do this - too easy to damage something with a procedure that isn't vital to the process.
Using a lineman's pliers, squeeze the two tabs of the hose clamp that is on the hose and slide it down the hose. In the post above, the orange circled area shows the clamp - mine has the 3 dabs of pink paint on it. Once you've slid the clamp down the hose, remove the hose. When you have removed all the oil from the dipstick tube, you will switch the oil extractor to this hose. Again, slide the oil extractor hose down until it bottoms out, jiggle it a bit to verify you've reached bottom, and following your extractor's instructions, remove the rest of the oil from your engine.
Now that you've removed as much oil as possible, the oil filter should have drained sufficiently. Finish unscrewing it from the threaded tube, and when it is free, quickly tilt it back and remove it from your engine. Use a rag/towel to clean the surface of the oil filter base. Take your fresh oil, dip a finger in, and lube the rubber gasket on the new oil filter, and install it where the old filter was.
Put the hose for the secondary extraction point back. Using the lineman's pliers, squeeze the tabs on the clamp to loosen it up and slide it up the hose to its original position. Remove the secondary fill plug - it's the one circled in green in the pic above.
The manual states that engine oil quantity with oil filter replacement should be 3.59 quarts. To avoid overfilling, I round down to 3 qts - I'll check it after everything's drained down and I'm certain of the level of oil in the engine. The manual states to split the amount of oil between the two fill openings - 1.5 qts for each. Using a right angle funnel, put it in the fill opening on the top of the engine (green circle) and pour in 1.5 qts. Once that's done, install the plug back, and move the right angle funnel to the dipstick tube. Pour in another 1.5 qts, and install the dipstick.
Allow the oil to flow down for a few minutes (10-15), and check the level. Top off until oil is within the range specified in the manual.
Clean up after yerself, ya filthy animal!
Here's the placement of my oil extractor, the extractor hose is in the secondary extraction point (the black hose).