Some of this may be obvious but I'd say to warm the engine up before draning the old oil. Remove the dip stick from the oil tank. The drain hose for the oil tank is behind the left side cover. It's a rubber hose that clamps to a keeper until it's needed. Loosen the clamp and have a catch pan or jug ready--tilt the hose into the pan to drain the oil tank. Re-attach the hose to the keeper when the tank is empty.
The spin-on filter is at the front of the motor at the front motor mount. You'll need something to conduct the old oil into a catch pan without it getting all over the frame and motor mount and generally making a mess. I have a shaped plastic trough from Drag Specialties just for this purpose, but you can use a piece of cardboard (a file folder works well) or a cut to fit liter soft drink bottle. Anything that fits around the filter up to the base, and extends beyond the left side of the frame to a drip point. This is all when the bike is leaning on the side stand.
I partially fill the new filter with new oil before installing it. About 1/2 to 3/4 full.
Another trick is to purge the old oil completely before adding the new. Draining the tank and filter mount by gravity will allow a small amount to stay in the case, not open to the oil tank or the filter drain points. After removing the old filter. clamp the oil tank drain hose back into place and fill the oil tank with about 2 1/2 quarts. With the filter removed, and the catch trough in place to the drain pan, start the motor and let it idle. The last of the old oil will be pushed out through the filter mount, and into the drain trough and pan. You'll be able to tell when new oil is coming through and all the old oil is gone. It will only take a minute or so. Watch the oil tank of course so it doesn't run dry but it will only take a short period of time and the oil flows slowly, so don't be nervous. When fresh oil is coming through the filter, shut the motor off, let the draining stop, attach the new filter, top up the oil tank and you're good to go. Oh, and I always stop about 1/2 quart short of the full mark on the dipstick to prevent blow-by to the air cleaner.
Hope this helps.