Instructions on installing pcm or ecm in my 3.6L

See your local repair shop or dealership to do this; you need a diagnostic tool for programming, including keys after done. Not a do-it-yourself repair. And, very very very unlikely that it is even needed for repairs unless it has water in it or has been physically damaged. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops