After you download it. Click on it to install it. Once it is
installed, when you go to Word and try to print the document you should
be able to see pdfcreator as one of the printers.
Choose the pdfcreator option and print. It will bring another dialog box, asking you for the pdf file name and such.
Note: keep the downloaded file (PDFCreator-0_8_0_GNUGhostscript.exe) and
install it on your other computers, if needed.