You can change the order of the blocks by moving them across a page.

Moving blocks on a page

Hover over any block and click on the icon in the top right corner:



In the new window pick a block and move it to the relevant place on the page by clicking on the arrows icon:



Important: you can only move blocks within a single page. To copy a block to another page on your site, see the article Copying a block.

Click on cross icon at the top right corner to get back to the editor:



Publish your site for the changes to appear live.