The rear most bottom plug is the oil tank itself.The middle and front plug are the oil screens in the lubrication path to and from the oil pump.Remove all three for the first oil change. Check the screens for gunk (shouldn't be any) and be careful as the screens are fragile.Just remove the rear most oil tank plug every other oil change.And the side plug (bolt) on the timing chest must be removed to drain the chest. Refill the chest through the front tappet opening (you'll see after removing the tappet cover).Check your owners manual for the cc's of oil needed in the timing chest. I use a small funnel and a turkey baster for this.And have a few shop rags handy!
It's that prominent large bolt head on the side, centered in the middle and right above the oil pump profile in the cover casting. It is aligned with the center of the crankshaft.Unscrew it and oil will flow out. And it has a smooth "stud" that fits into the donut seal of the oil pump drive gear at the right side of the crank.
Ridgerunner - I recall you've got the AVL Classic?The AVL motor has a different oil pump setup from the iron motor... don't think it uses the same worm gear and removable quill bolt that we're talking about.Now about "a lot" of stuff in the oil... I'd probaly do another inspection/change in a couple hundred miles and start talking to the dealer if it's still "making metal"...Mike ans Stumpy in Michigan