Karma is simply the law of causation. Just like an apple tossed in the air must return to the ground, a thought deeply focused upon has it's eventual reaction. A thought given attention and interest becomes a feeling, a feeling becomes a desire, desire leads to action, and action has it's eventual re-action. It all starts with a thought and the degree to which it is focused upon and identified with.
Karma Yoga is the practice of freeing one's Self from the bonds of karma. It is the practice of selfless service / allowing thought and action to happen naturally, without any sense of doership. Thought and action may still happen, though the inner Silence witnessing all thought and action becomes the primary focus. When all sense of doership ceases and one is fully established in the silent recognition that they are Unchanging and Ever-Peaceful, even in the midst of thought and action, then one can be said to be free from the bonds of karma.
