I’ve written an idea down and gone back to it and not understood what I even meant, or if I did the details that made the idea interesting to me in the first pl

I’ve written an idea down and gone back to it and not understood what I even meant, or if I did the details that made the idea interesting to me in the first place were gone. I don’t think you have to flesh out an idea on the spot, but I would recommend writing down all the details of your idea and include any fleshing out of the idea your brain already did on its own.