There is a simple recipe on the side of the canister of Pillsbury Shake-n-Pour flour. Since I never bake from scratch (DH says he's looked for scratch in the grocery store and can't find it), this is the only flour I have on hand. It is so simple, even I was able to follow it. I believe it calls for 2 T cooled pan drippings, which you can refrigerate and skim off ALL the fat, so the gravy is fat-free. When you cook your roast or chicken, pour the pan drippings into a container and then keep them in the fridge for this purpose.
I think it was a cup of hot liquid (water or broth). Heat in a pan, add the 2 T cooled drippings (I used a little more, and when I made it they were not just cooled but jelled solid and I heated until they melted), sprinkle the 2 T flour while stirring. That's it.