How do I delete/copy/move pages that contain subpages?
The so-called Recursive Deleting and Recursive Copying - i.e. deleting/copying pages with their subpages - is a feature disabled by default for users to prevent unintentional deletion of large parts of the page tree. However, you can enable the feature yourself:
To do so, click on your name in the top right corner of the backend and then on "User Settings" below it. There, select the tab "Edit and Advanced functions". Here you can activate a checkbox with the following name: "Recursive deletion(!): Allow ALL subpages of a page to be deleted". In the "Recursive Copy" field you can also specify a number of sublevels to be copied (e.g. 5). Confirm the activation of the features by clicking "Save".