If you wish to reorder your courses modules.
Select the course you'd like to edit.
Click 'Edit Course' to start editing course contents.
Once you've done that you'll arrive at the course creation page which looks like this:
Hover your mouse over top of the 3 lines located beside the module you want to reorder:
Then select the module using your left finger on your mouse. Move your mouse to drag the module up or down.
When you've moved the module to the correct location. Release the mouse button to drop the module into place.
Note: Your new module order will not save until you've selected the 'Save' button down below after changes have been made.