Formal:
* ਮੈਂ ਕਥਕ ਦੀ ਕਲਾਸ ਦਿਆਂਗਾ/ਦਿਆਂਗੀ। (Main kathak di klass diyaanga/diyaangi.) - This is the most formal way to say it, using the respectful form of the verb "to give."
* ਮੈਂ ਤੁਹਾਨੂੰ ਕਥਕ ਸਿਖਾਵਾਂਗਾ/ਸਿਖਾਵਾਂਗੀ। (Main tuhanu kathak sikhawaanga/sikhawaangi.) - This literally means "I will teach you Kathak," which is a more direct way of saying you will give a lesson.
Informal:
* ਮੈਂ ਤੁਹਾਨੂੰ ਕਥਕ ਸਿਖਾਉਂਗਾ/ਸਿਖਾਉਂਗੀ। (Main tuhanu kathak sikhaunga/sikhaungi.) - This is a more casual way of saying "I will teach you Kathak."
* ਮੈਂ ਕਥਕ ਵਾਲਾ ਪਾਠ ਪੜ੍ਹਾਵਾਂਗਾ/ਪੜ੍ਹਾਵਾਂਗੀ। (Main kathak wala path padhaawaanga/padhaawaangi.) - This means "I will teach the Kathak lesson," and is more specific about the content of the lesson.
You can choose the most appropriate phrase based on your audience and the situation.