Someone recently mailed to ask “I’ve got an idea for a game – how do I get started making it?”
The high level of the question, implies that the asker is completely new to making games.
Games tend to require a lot of time spent programming, making artwork, and then putting it all together into a game.
First, I recommend concentrating on learning how to build games in general – instead of focusing on building your dream game. In the early days of learning, it's great if you can just build 'Asteroids' - you can build your Quake-killer later on.
If you’re ‘pretty good with computers’, then a fun and free way to get a taste of game development is to install Unity and follow this tutorial. Following the tutorial is kind of like getting an ‘Airfix’ model airplane and assembling it – most of the hard work has been done, but there’s still challenge in working through the instructions.
Going through this will show you bits of program code, and how art and animations get combined to make a game.