I have only used coffee once but my beer turned out amazing, even local brew club wanted to pass it around.
Double handfull of whole beans into the secondary, then start sampling until it gets to where you want. Did not need to sanatize, cold steep the beans etc doing it this way. Its probably less efficient, but its flexible and easy!
if you get the coffee hot it will leach acids that will effect your beer in negative ways so cold steeping/brewing or whole beans is the way to go.