What to charge.. I can't say. In fact no one can, really. It's up to you to determine your rates.
How to charge may be a different matter. Realize that one-on-one training is a premium.
If someone merely wants to learn something there are always dozens (or hundreds) of online tutorials, college courses (even community college), and online video training packages. These could all be utilized by the cost-conscious consumer. Getting direct, interactive, personal, training from a professional in any field is a premium service. There should be no discount for this service even if it's not your standard service.
If it were me, I'd charge my standard hourly rate regardless of what may be the topic of training. This is done because my rates are set to cover costs for my time, not for that I'm doing during that time period. While it may be true that there is much less overhead in teaching, compared to directly creating something, the overhead charges built into any hourly rate would compensate me for the additional effort in explaining something multiple times in various ways or creating samples which would otherwise be unusable.
Be certain to set clear expectations. If possible create a bullet list of you plan to train.. a syllabus basically. This will give the client something to reflect upon to see that there is a method to when any particular aspect may be the training subject. You can also explain each bullet a bit with things like "This part is going to feel like you aren't making a great deal of progress, but it's overall necessary for everything to come in the future."