Very sorry to post again, but I do have one other question:
So far, I have created the most basic child theme, containing only the style sheet. How exactly do I go about adding templates, though?
At the moment, there is a modification I've made to page.php that I'd like to preserve. In the codex it says you can, but I'm not entirely clear on how. Is it just a case of making a blank file with that name, or does it require a header like style.css has to refer back to the original?