Pam has the correct suggestion for getting a Word document up to Amazon, though I would focus on the free LibreOffice. The LibreOffice Writer documentation is here.
You can rule out sending a Pages v5 exported PDF to Amazon Create, and there is the reality that your Pages content exported as Word, may suffer image alignment issues.
The LibreOffice download will take you to an optional donation page. Do nothing, and the download will start by itself in a few seconds. Once you get LibreOffice into the Applications folder, open a new Finder window, click on Applications in the Favorites panel. Right-click on LibreOffice, and choose Open. Once it launches, select Open again. This is a one-time ritual because it was not from the OS X App Store. Drag it to your Dock, and subsequent launches are a single click.