Karma Yoga is selfless service.
This is the yogic path of action. You are practicing it whenever you are acting selflessly, without thinking about success or reward. This path is valued for purifying the heart and reducing the influence of the ego on your words, actions, and interactions with others.
Practicing Karma Yoga is the best way to prepare yourself for silent meditation. It suits people with an active outgoing temperament.
At the yoga retreat, Karma Yoga will include assisting with preparations for the meals and cleaning up afterwards.