I think Tom Burch's comments are right on the money. I would only like to add two things:
1. If the lesson was not satisfactory, let the school managers/supervisors know. I won't speak for other schools, (but I may be), but we guarantee satisfaction. We will refund or reteach (within reason).
2. Having done all that Tom says, make sure that you take some responsibility for yourself as a learner. Be ready, be a sponge, be fully present and relatively ego-less, be open, be empty, be in a beginner frame of mind. Realize that failures are part of the process and you will have failures AND successes in order to move forward.
One hour? Half day? All day? Full week? It depends on your preferences. I can get a lot in fifteen minutes, if I'm ready to learn. As an overall rule of thumb, though, I would say that some multi-day lessons are probably the best as you can develop a nice cyclical rhythm of new info, guided practice, solitary practice, consolidation, forgetting about it, and then back to new info. Use your intuition on this. It will work for you because you even asked the question.