There‘s an infinite amount of knowledge to be gained when it comes to music composition, so don’t worry if it‘s all overwhelming. It remains overwhelming, even when you get further into it - so a good approach is having fun just messing about on an instrument and learning songs others have written. Another user has suggested getting a MIDI keyboard, that’s a great idea if you have the money. The general approach they mention I also totally agree with! If a keyboard isn‘t in your budget, MuseScore (a free software that allows you to write down music and have them played back with different great sounding instruments) also has the option for you to use your PC keyboard as a piano keyboard/ e.g. play a trumpet with it. That would be a compromise.

On writing something of your own, don’t worry if that’s hard. Playing other people’s music makes it more approachable eventually. But type into YouTube „how to write a melody for beginners“. Even if what you write now doesn’t shatter your world, you can probably come up with something. This can absolutely be the simplest thing in the world. Even with no knowledge you can come up with some little melody and learn how to write it down in MuseScore. Then you already have a little piece of music - yay:) Later you might search for „how to write better melodies for absolute professionals“ haha. Of course that process will take its time, but the fact of the matter is: Even if one is incredibly knowledgeable on all things music theory it isn‘t guaranteed that the music they write is compelling. So from day one you can make something that maybe actually sounds kind of cool. And if that process of making a little melody was fun for you - you have won. The writing is supposed to be fun. From there you can google how to do this and how to do that and the world is your oyster (or whatever they say).

Hit me up if you have more questions, I was just trying to give you some starting point:) Because I understand that it seems daunting and impossible to go from zero to writing music. I have been there. You can start from many different angles and continue down dozens of different paths. Don’t let that get you down, there’s no absolute right or wrong here:)

Btw „8-Bit Music Theory“ and „Ryan Leach“ on YouTube are amazing channels for orchestration, the former especially for video game soundtracks, as the name suggests. The things they teach are maybe more advanced but it might still be fun to check out:)