Tip: to avoid future confusion, it's a good idea to delete or rename the original copy, or move it to a different folder (so you don't mistakenly end up editing the old version!) In doubt, look at the title bar (top "border") for the name of the document you're currently editing.
Caution: to rename a document and change its file type, "Save As" first to convert format (typing a different file extension will create problems), and optionally delete the original file.