Add Post-it notes

Often times as I am building out my workflow, I think of an idea that I could add to that branch, but need more contemplation. I'd like to be able to add a "sticky note" (not an actual step to the workflow) to that area with the idea or function I could add, so that when I come back to my workflow, that idea is there. If I write it down in my notebook, it can get lost because I have so many notes I am taking.