Saving an article/question as a draft is a great way to keep up with what needs to be redone/edited or written. With Helpjuice, you can always preview drafts, live, as long as you have the URL. Of course, they aren't indexed by the Helpjuice search engine, nor shown to users that are using your knowledge base.
Assuming you are logged into your account, to save a question/article as a draft, all you have to do, is, regardless if it's already saved (as published/draft), just change the switcher to Draft side.
Later on, of course, if you'd like to PUBLISH the question, all you have to do is click change the switcher to the Published side.