I don't see any button to save a draft of a Story Pin, so that I can come back later to check everything. Since I don't want to risk that the work done disappears, I haven't tried closing it without publishing. Is that how you do it? Thanks!
My experience is that when you close the tab, it will show up as a draft. It's happened to me many times. You shouldn't run into any problems, but it's always safe to try one.