By following a few simple steps changing the oil is not difficult.
-run the engine for a few minutes to allow the oil to drain more easily
-use Generac branded filters that will ensure proper fit and function
-Do not over fill the oil as this can lead to premature failure of oil seals along with other problems
Some other items you might consider doing at the same time.
-gap the engine valves (this important step should never be skipped)
-replace the spark plugs
-replace the air filter
-check the battery (replace every 3 years)
When it comes to generator maintenance is the little things that make the biggest difference.