Setting Up The Raspberry-Pi with Pi-Force Tools
To assemble your Adafruit Pi-Plate LCD/keypad there is an excellent guide on the Adafruit website.
The official repository for Pi-Force-Tools can be found on GitHub. However what you really need is to download the SD card Image. This can "burned" to the card in windows using a program called Win32DiskImager. This is how most Raspberry Pi images are placed on the SD card. The process is as simple as selecting the image and selecting the SD card, but even still there are lots of guides. There are guides for Linux as well.
Once the image has been burned You should be able to install it in your Raspberry Pi with the Adafruit Pi-Plate and plug in power to check that your Pi-Plate and SD card image is functioning properly. Chances are you'll need to adjust the contrast to see anything, also note that it could take 20-30 seconds to fully boot.