The manual was written for QGIS version 2.18 (Las Palmas), which is slated to become the next Long Term Release version. Because there are enough differences between versions you should download and install 2.18 if you are taking the workshop.
- MS Windows users: QGIS 2.18 (32 bit) - or - QGIS 2.18 (64 bit)
- MAC users (OS X Mountain Lion and newer): Download and install the dmg image QGIS 2.18.
- Linux users should consult the QGIS download page and follow the instructions to download the 2.18 release version for your distro.
The QGIS website gives you the option to download the Latest Release or Long Term Release - this workshop always uses the Long Term Release. 2.18 Las Palmas is slated to become the LTR this fallrelease.