Kink Classes are offered through various venues and agencies and typically teach information about niche techniques, protocols, disciplines and forms of etiquette. Often these classes will also include a Demonstration when appropriate.
Attending the classes of more experienced presenters in the BDSM community can be a great way to gain a lot of the subtle nuance and hands-on experience you can't gain from a wiki or book.
Consider studying under those that are well reviewed as experts on a piece of subject matter you are interested in.
Remember to do your due diligence research on the presenter of any class you are interested in to make sure the information you are getting is correct and up to date. Vetting also helps ensure that the class you take is the class which will teach you how to be safe and keep your scene under control. If a presenter has been described as violating consent, especially in a class setting; using unsafe methods; or trolling for potential partners in a class setting, these may be unsubstantiated rumors, or they may be valid concerns. Research your presenters and choose who you learn from wisely.