Slides
To change the order of your slides, hover over the slide, and then using the icon in the top right corner, drag and drop it into the new position.
You can also re-order slides in the editor by grabbing the empty area on the left:
Components
To swap a component with a different one within the same slide, hover over one and simply drag and drop it into the desired position.
To move a component onto a different slide, click and drag the component's setting menu in the editor.