Maria,
There is nothing inside your Pages document that is meaningful to any application on Windows — or human readable, because Apple uses proprietary data formats that only Pages applications on OS X, IOS, and Pages for iCloud can open and read. The OSXDaily article implies that Microsoft applications can read those internal structured Pages files, or the PDF, and that is simply nonsense. A complete waste of time renaming Pages documents.
Ideally, that Pages document content is exported to Word (.doc/.docx) format on the Mac, and that Word document is provided to you.
Access to the free iCloud dot com from a supported Windows browser (Firefox 41 works ok) — gets you access to Pages for iCloud. This web application allows you to upload that .pages document on your Windows machine to iCloud. Once this document is opened there, you can click a wrench icon on the Pages for iCloud toolbar, and choose to Download a Copy. A panel is presented that allows you to choose a Word document format and a .docx is downloaded to you on Windows. Now, you can access the converted Pages content with any Windows application that understands the .docx format.