Developing the game is just one part of the work; releasing it to be successful can be a huge task. Sometimes, it can cost more than the game itself. So, unless you are making a game for fun, if you want to make your game for a living, you will need to learn how to manage releases or hire people that are capable of helping with the pre-release, release, and post-release phases of your game, which can be a smart move.
Of course, this chapter just provides a simple introduction to this big topic, so I would recommend that you read some extra material if you want to take this part of game development seriously. A very well-explained and bite-sized source of information on this topic is the Extra Credits YouTube channel, which provides short videos to convey valuable information. Also, there is a great book called The Art of Game Design: A Book of Lenses, which provides a thorough introduction to game design.
Congratulations, you have finished part 3 of this book! You have...