When you wish to alter questions, you simply click on the given question to change anything you'd like, from the number of response alternatives to the settings and text.
When you have launched the survey you have less options to edit. You are unable to change the number of response alternatives. If you must do so, you can change the settings of the question to 'Hide question' in order to hide the wrong question from the respondents while you create a new question.
You cannot change the order of the questions. If you create new questions after launch then be aware that you need to choose which number the question will be before creating it.