To get Word documents onto your iPad - and use in Pages - you will need to use either iTunes to transfer them (http://www.apple.com/support/ipad/syncing/) or optionally:
- Install Safari for windows and use that to access iCloud and upload documents, or
- Install the iCloud Add in on your PC (allowing you to use IE or other browsers).
For file transfer, installing Safari may be the easiest option.(http://www.apple.com/support/icloud/documents/)
Basically you upload documents to iWork on the iCloud. Pages will automatically pick them up for downlaoding and editing.
Anotehr option to consider is a cloud service such as DropBox. It allows you to open files in any number of apps, including Pages.