There really isn't much to do on these.
-Run it on a hose to flush with clean water. Keep it trimmed down after and all the water will run out.
-Drain and fill the lower unit. Pull the top screw then the bottom screw and let it drain. Then fill from the BOTTOM screw hole pushing the new oil in and up. Once you see oil coming out of the top plug both holes. This way pushes any air up and out of the gear unit. I found a nice gear oil pump at Gander Mountain that has a threaded tip that just screws into the lower unit gear case, made it very easy.
-Pop each spark plug and fog the cylinder. My motor is EFI so this is all I do. If you have carbs you can spray fog oil into the intake while its running on the hose and get a better fogging.
Feel free to PM me if you need more help.