I just did mine yesterday.
when I last filled the fuel tank, I added stabilizer, then went for a rid to mix it up
warm up engine using earmuffs on it
change oil and filter
in my dink tank, I mixed injector cleaner, marvel magic mystery oil and stabilizer with the fuel - I disconnected the fuel hose from the intake to the engine and attached the hose from my dink tank with the mixture and ran the engine for 5- 10 minutes.
while running the engine, I ran -50 pink antifreeze through it. I used the camco winterizing tank attached to the muffs.
That's it!
If you have fuel injection, don't spray fogging oil thru the air intake, you can unscrew each plug and spray some into each cylindar.