Registration _validate vs _execute in the documentation

Is there any chance someone can have a look at the documentation for the _validate and _execute (POST) options in EventRegistration? The examples and documentation are completely different, there's no payment data in the _execute example, etc. It would stand to reason that the difference between the 2 would be minimal, as they're doing everything the same except processing the order but while I have worked out the payload for the _validate call I can't do the same for the actual registration one. Any additional info would be helpful. Thanks much.