The Canon Digital Learning Center has made the AF settings guidebook for the EOS-1D X Mark II available for download.
From Canon DLC
This downloadable .PDF guidebook from Canon’s engineers will clarify many of the details about the incredible AF system in the EOS-1D X Mark II camera. Information about the effect of different AF Cases, and various other menu settings, is spelled-out to help you make the most effective use of this camera and its powerful AF capabilities. And, keep in mind — the vast majority of these apply to the 61-point AF system in Canon’s EOS 5D Mark IV camera (which uses the exact same AF sensor), so most of this will be useful information to owners of the Mark IV camera as well. We’re confident having access to this file, on your computer or in a mobile device, will answer many of the questions which may arise as you use either of these cameras.