Training could be done through the GUI in the form of “interactive tutorials” based on hand-holding the user from start to finish on a predefined set of RAW images and tooltips that describe what should be done and what each slider / setting means.
A couple of RAW images for portraits, another few for landscapes, some with tricky dynamic range situations, and so on…
The output is then verified (allowed range of settings) and the user is notified (success / failure).
Something like an interactive version of @s7habo 's editing moments:
Mixed with output verification based on unit tests, similar to this: