Click Download tab and register your Pantone Book (you need a serial for that, it should be somewhere in the book).
After that you may download and install Pantone Color Manager software. With it you should be able to add new books to your InDesign. I have not tried that myself yet, so I can´t help you any further....
Pantone just released new downloads for the Pantone Plus color books. I saw an article about it at CreativePro.com. The article with links to the software is here: http://www.creativepro.com/article/add-pantone-plus-library-adobe-apps-free
The numbers in the swatch books don't necessarily mean much, either. As far as I know Pantone has never released the pres profile for which those numbers were developed. If you check the box to use standard Lab values for spot conversion the numbers you see will change depending on the destination and working profiles, even if they match the book with the option unchecked, and your color match is likely to be better as long as the corect profile is used and is accurate.