You'll get lots of different responses, because there are different ways to go about it. I like to add coarsely cracked beans (quality and freshness is big) to a fine mesh nylon bag, like a paint strainer bag. Bag gets added after beer is at FG, then you sample every day until the coffee character is where you like it, usually around 2 days. Then pull the bag and package. 4 oz is a good amount to use. Good luck.