This is a very high-level overview:
- You figure out what sort of game you'd like to do. How much time you have for such a project?
- Then you plan what your game actually will do, how would it look, and what sort of features it would have.
- Then you choose your tool for the job. Note: your tools available may have a huge effect on what kind of games you can do. (E.g. creating a number guessing game is a whole lot different from creating a 2d top-down shooter, which is a whole lot different from creating an open-world multiplayer survival game).
- Then you get planning, what steps to take to do your project. Based on the project the planning may be simple or rather complex. You could do a simple math game in minutes to hours or a 3D game in months, or rather years.
- Get the team (or solo?!) ready and start prototyping.
- Keep testing, and prototyping until you get a working version of the game.
- Start polishing, testing, and modifying to meet the requirements.
- In the meantime, if you want to monetize it you need to start advertising.
- When the game is ready to show to others have others test your game. Get them to provide feedback.
- Work on the feedback (fix issues, add more features, fine-tune things).
- Have more rounds of testing, until you're happy with the satisfaction of the people who are going to play the game.
- Release the game.
- Keep providing support to your players (fix bugs, implement new features, add new content, provide technical support).