You can easily change the questions & questionnaires' group display order from your dashboard!
Go to Content Customization page, and per question or questionnaire group you will notice the reorder button. You can move either up or down the question or questionnaire group, in order to set up the order of the questions & questionnaire's groups as you wish!
Additionally, you can change the group of a question.
To do so, click on the question's settings and edit the group the specific question would be displayed.
Step 1: Question Settings
Step 2: Select Group
Step 3: Press Save, to make changes published !