I have a kohler command 18hp snapper that is smoking bad it is a blue smoke how can I fix it myself what it is that have to look for?

That sounds like cylinder or rings or a clogged breather

Overfilled with oil?

Hi,
First check air filter for dirt or oil contamination. Check around engine for signs of leaking and check dipstick. A common cause of oil being pushed past rings is air entering crankcase.
Alternately, if service of engine has not been at the regular intervals specified; change oil and filter, run 5 hours and change them again. Only use 10W30 if it is OHV Command engine.
Peace,
Clarke