Pretty simple, just did it this morning.
Direct from the manual (except my additions in red):
FINAL GEAR OIL
• Keep the motorcycle upright (lean on kickstand so the old oil it goes in the pan).
• Place an oil pan under the final gear case.
Remove the filler cap 1 and drain plug 2 to drain oil.
• Refit the drain plug 2 (now stand upright, I leveled mine with a jack). Pour the specified oil (SAE 90 hypoid
gear oil with GL-5 under API classification) through the filler
hole until the oil level reaches the filler hole.
• Refit the filler cap 1.
"Final gear oil: 200 – 220 ml (6.8/7.0 – 7.4/7.7 US/Imp oz)
In comparison to the Diff oil used in your car or pickup truck.... the final drive oil in our bikes is way over serviced.... - in comparison.....Oddly I've seen it written both ways for the draining. Owner's Manual said drain on kickstand, Service Manual said stand upright. (Both agree on filling upright BTW).
To me it almost looks like draining on the sidestand there is the potential to leave some on the "lip" where the housing changes size before you get to the drain hole.