2. Setting the margins (in the page layout) to zero
3. Importing the graphics files - one per page.
4. Zooming the graphics to exactly match the page size.
5. Printing the word file on one of the pdf printer emulations (e.g. doPDF8 - there are others available).
If you already have .pdf files - but one file per page scanned:
Amongst the 'other tools available' is the PDF Creator24, which is not only installing the pdf printer function described above but also supplies a "combine pdf files" function.
One of the download links where you can read about the features and get your free copy: