Because these are what you'll be [using 80%+ of the time](https://en.wikipedia.org/wiki/Pareto_principle).
| Command | Effect |
|-------------|----------------------------------------------------|
| `do` | **Get** changes from other window |
| `dp` | **Put** changes to other window |
| `]c` | **Next** Change |
| `[c` | **Previous** Change |
| `:diffthis` | Type in each split window to diff existing buffers |
| `:diffoff` | Type to turn off diff mode |
Use Ctrl+w, Ctrl+w to switch between windows. [Via](https://amjith.blogspot.com/2008/08/quick-and-dirty-vimdiff-tutorial.html).