You can easily drag and drop questions to change their order on your form. To do this:
In the form editor, hover over the question you want to move.
Click and drag the 6 dots that appear to the right of the question.
Release the move indicator to drop the question in the desired spot, indicated by the green line.
To drag and drop images, videos, and breaks, click anywhere on the element and drag it to the desired place. You can also drop and drag whole groups of questions the same way by clicking on the dots on top of the question group.