Your outline is a dialogue you have with yourself around the story, helping you to find the structure before you begin to write. It is a map that shows the many different routes you can take to get to the end. It is a guide, not a prison, as brief or detailed as you want or need it to be.
Each major plot-point is revealed in a scene. Write vividly. Show your story, don’t just tell it.
An advantage of writing an outline is that if you get stuck on one part, you can put that aside and move on to the next. And as you write your outline, you will find that you will see at a glance what has been missed and what needs to be written.