I'm writing a story with multiple branches. so from chapter 1 you could go to chapter 2a, 2b or 2c. I want these to be in this exact order top to bottom. If I publish them in that order is that how they will appear? Does the order I have created them in matter?
They will appear in creation order and as displayed in the chapter preview. You could create dummy chapters just in case to keep order
Please do not do this. We now have a reordering function. The new post notification only happens when you first post, so making empty placeholders spams all your followers for nothing and then doesn't tell them when actual content appears in those existing placeholder chapters.
As it might still be useful to have a chapter earlier than it is filled with content (e.g. for planning ahead in Game Mode stories), you can create draft chapters in the right place without publishing them. When the chapter is finally published, it will appear at the place it was drafted. (That doesn't work on unpublished stories, as all unpublished chapters will be published.) For most cases, reordering is now the way to go.