If you are blending, just use three notes to begin with. You can always experiment more when you get the hang of it. Your first blend should be 10 drops in total. A good rule of thumb is to use 30% of the top note, 50% of the middle note and then 20% of the bottom note.
When you have mixed your blend, let it settle for a day or two. This will give you the best chance to see if it is going to be a viable option for you and it also lets the oils combine as well. When you have left it for a few days, you can then do another sniff test.
Place one drop on a strip before you breathe it in. Think, what does it remind you of? Write down your thoughts and write down what you’d like to change. This is one of the best ways to know if an oil blend is working for you or not, so do keep trying with that until you find the perfect one