A page can be moved by dragging and dropping the page in the page tree. Grab the page by the page title, not the page icon. It can be placed in between two pages, or on top of an existing page to make it a subpage.
Copy a page by doing the same thing, drag the page you wish to copy, but holding Ctrl button on your keyboard before dropping the page. Note that on Mac it is the actual ctrl-button you use, not the cmd.