In very simple terms, karma is the result of our actions and thoughts. There are many kinds of karma. Some are good, some are bad. Where there is action with attachment, there is reaction or consequence. Karma is when mind is uniting with a subject, and then after we have an attachment for it. In other words, attachment attracts karma. It is like an endless cycle that we are bound to because we are attached to our senses. The ordinary person is creating more and more karma every day, and is also reaping the fruits of karma from previous lives.
We cannot stop our work. We have to face our karma and accept it with a balanced mind. In the Bhagavad Gita it is written that action is superior to inaction, otherwise we cannot even look after the body. We cannot avoid our karma or stop our activities.
But we can free ourselves. When you have a good sanskara, or influence of the previous life, you are receiving Kriya Yoga. Kriya Yoga destroys your karmas. It is similar to when we fry a seed, because afterwards it cannot germinate. In the same way we can burn our karma through the fire of knowledge. Whilst we do not stop our work and we continue to take care of our responsibilities, we can free ourselves of attachment. The moment that we are doing Kriya Yoga practice, our mind is not involved with the external world, and the karma we are carrying is slowly destroyed. And then desires end.