How do I find the problem

1st make-sure battery end are clean ck all fuses look and see
if headlight are bright then cke charging sustem 12.5 idle
13.5 1000 rpm. Then take to auto zone and use obd2 and find
a code what color is the smoke if it white blown head gskt
burning antifreeze of blue smoke valve seals stuck rings
how often do you change oil every 3000 miles I hope this will get
you started please rly when you have more informationinformation