Start with a piece of graph paper and a large cup of coffee. Take your time and sketch out some strips WOF in pen and then use a pencil to mark off pieces. You should find that as you do it, it will start to make sense. Don't try to figure things too exact. Leave some extra at end of strips (also figure WOF at 40" because of different fabrics and selvages). Don't hurry yourself and you should start to see how it all works. Take one block and mark those pieces up and then do a second and maybe a third. Now you should see how they fit into the strips and you can multiply to figure how much for 8 blocks, 12 blocks, 16 blocks, etc. Look at the small picture instead of the whole thing to start and you won't overwhelm yourself. (Also, try this out with a very simple block like a split rail until you see the way it works.) Good luck.