There are lots of different approaches to plotting a story and every writer has their own way of doing things. One way is not better than the other. What way is best, is that way that works best for you, as a writer. If you have a story idea in your head that wants to come out, you owe it to yourself to do whatever it takes to get your story down on paper and out of your head. Whatever method you use is up to you. If you don't know that is yet, don't be discouraged. There are lots of different approaches you can try.