What I do is melt the butter in a pan and then start adding flour, bit by bit. Yes, you need equal parts butter and flour, but adding it a little at a time helps to get some of the lumps out. If you still have a hard time, add slightly less flour than butter. But only slightly. After you have your butter and flour added together, it will look really lumpy. It is OK. Keep stirring it around, to cook off the ‘flour’ taste, and then add your milk. As the milk heats, it should break down those lumps. I’m sorry, I never measure these things out exactly, I just put a little butter in and then add flour until the mixture begins to get thick and chunky. As for the milk, add it slowly, and you know you have enough milk by doing the ‘back of the spoon’ test. Dip the back of a spoon in the sauce and run your finger down it. If the part where your finger made a line does not fill in with sauce right away, you know it is thick.