It sounds like everything you mentioned falls under the heading of software project planning. Are you familiar with those techniques already and possibly asking whether those should be applied to personal side projects?
To some extent, yes, my question is about how "other" people plan their ideas and projects. I'm familiar with those techniques but I would like to know how others' timeline from an idea to a product looks like. When do they start getting other developers to work with them, how easy it is for them to convince others, etc.