How does someone get into music composing?

Here is a pretty comprehensive answer.

You would have to be like my Dad who loved music, had music playing in his head, and learned to read music. And it helps to have some talent!

Assuming you haven’t yet started, well, first you need to start composing music. Obviously.

But seriously, you need to have a portfolio of compositions… to start. Then you need to get that music played. Assuming you can already play at least one – preferably several – musical instruments (or synthesizers or however you expect this to be played), then you can do the composition and playing yourself, to start.

And then it needs to be recorded. Because the most essential part of your portfolio is music that can be listened to. (I doubt whether many purchasers of musical scores can read the things and sound them out in their heads – it’s a physical medium, after all, of sound waves interacting with ears.)

So… compose a lot of music and get it played and recorded.

After that, it’s promotion, marketing, and exposure to those who would purchase the tracks and commission more music of the style that you’ve proven to be capable of.

A lot will depend on your ability to network with others who can use and promote your music right away: bands who will play it; advertisers who may commission jingles; lyricists, poets and songwriters who want musical scores to accompany their work, or who can write to suit yours, and, as you note, game developers who want themes and scores for the action and elements of the game.

Another starting point for you at the early part of a career in this field would be to seek out independent and documentary filmmakers who need scores for their works but can’t afford “big name” musical talent.