A course administrator can change the ordering of course modules and assignments within their course. Moving an assignment only changes the ordering, it does not affect "completion" status for each student. So for example if you move a quiz to a different module in the course, any students who have already completed that assignment will still see it as a "completed" status in their history.
First log into your admin dashboard at www.heatspring.com/account then click the "classroom" button for the course.
To move an entire course module, click the "up/down arrow" icon near the other editing buttons for that module and drag it to the correct place in the course.
To reorder an assignment within a module, use the "up/down arrow" icon for that assignment to click and drag it to the correct place in the module.
To move an assignment to a new module, instead click the "pencil" icon to edit the assignment. When editing the assignment under the "Module" section dropdown menu, select the module where you want the assignment to live. Then click "update assignment". At that point, you may need to drag the assignment with the "up/down arrow" icon to the correct spot in the module based on how you want the assignments ordered.
Also note that there are auto generated modules and assignments created by HeatSpring that are standard assignments which cannot be reordered or edited and will not have the "up/down arrow" or "pencil" icons available.