In order to understand Karma Yoga, you have to understand what is Yoga? Yoga is not to do a headstand or handstand. If it has been so every gymnast and tom dick and harry would have been a yogi.
If you want to have a better understanding read here what is Yoga ? Krishna says ” Samatva Yog Uchayate” So, In short, you can understand it as attitude to have a Balance approach.
Now when we add a prefix to it like Karma, which means Your Activities or say action then it means a balanced approach in your activities.
But in order to reach a stage of Karma Yoga, you have to first reach the stage of yoga (i.e. balanced approach) in your mind and that can be obtained by Gyan Yoga.
Now, what is Gyan Yoga? In chapter 2 verse 33 You can read about it for details. I will explain a little bit about it. When Arjuna was telling Shri Krishna that he wants to quit. At that moment Shri Krishna tells him that if he quits then his competitors will mock him. Will say words that for a respectable human being is not acceptable, either you die in this war or you win it and rule the world.
This teaching what Krishna gave to Arjuna is what generally your wellwishers give to you when you feel disoriented isn’t it. This is simply said to be as being practical in your life and this Shri Krishna term as Gyan Yog. To have a balanced approach regarding what your goal should be and your approach towards your goal. To excel in whatever field you are and to not quit it. This is because if you have been doing something for 30 years or say even 5 years you must have gained some expertise in it.
So Now what is Karma Yoga and how to master it or say practice it?
Shri Krishna says that Human can’t exist without doing any Karma for even a single instance of time. This is because all living beings are bound to perform some karma forced by the governing laws of nature. Hence if somebody is saying that he will not be doing any worldly work because he is a yogi is fooling himself and the people around him. Chapter 3 verse 5 to 6
Shri Krishna here uses a term Yagya around here for a stepping step for Karma Yog. Some people say Yagya means lighting up the fire in cow dung and offering ghee to it but did Krishna really wanted Arjuna to perform such activities in the middle of a war. Also, Krishna is all the time talking about the senses, the mind, about the various human feelings and out of sudden why he will talk about something so vague.
Here again, Krishna is talking about the fire of self restrain, self-control, burn your desire in self-control, but he also talks about this being a gradual process rather than an abrupt process. He talks about developing the Devas within you and these Deva will, in turn, develop you as a better person. Now, what Devas mean? Like Indra Deva which is actually your senses. Indriya in Sanskrit means sense. If your senses are in your control this world will be Heaven or say “Swarga” for you. That’s, why it said that whosoever wins over Indra, rules the heaven.
Now how to develop these restrain, restrain are adopted by practising or say reading good books. Books of self-awareness Adhyatma is made up of two words Adhyan plus Aatma. Adhyan means to study and Aatma means self. So it means To study yourself or say to Know your self. When you will become self-aware you will know what to eat. Because you will realise that you are part of this nature and you are because of this nature. Start eating real food rather than cola, soda, and oil and lots of lots of bullshit which is available today for you to eat in the market.
If your Karma of eating is not good the outcome of your eating Karma will not, in any case, be good. As the Devas say Indira that is your senses will not develop and hence, in turn, you will not develop.
I hope I have given some basic understanding to you regarding What is Karma Yoga? This is a very vast topic and if you want to understand it even better you have to read Bhagavad Gita. If you have any doubts please feel free to contact me.