It's an amazing thing to me that we even have ideas. Now I think I'll run up a tree.
Some ideas do arrive fully formed.
Then you set about exploring, playing around with things, coaxing the idea to become more than just a wisp. Sometimes you have a big lump of clay to work with, sometimes you've just got a only little piece, and you keeping rolling it around and gradually adding more clay to it. And I go from there. I think that one can keep making up different ways to make music. Different questions to ask.