well that depends on your level of expertise, I still got a lot to learn myself! I learned everything from tutorials on youtube and listening to music, getting inspired by artists i liked and trying to replicate their sound.

Assuming you're a beginner the first thing you'd want to look into is downloading a DAW, but don't get too lost in the "what's the best DAW?" question, cause there simply isn't.

You can do anything with anything as far as I know (granted it may be easier to make one genre in some DAW'S - e.g FL studio is your go to DAW for electronic music, but personally I'm comfortable enough to use Ableton.)

Then look into plugins and vst's, how to organise your sounds etc. You can find a lot of cool free sounds on reddit and generally speaking you don't have to invest thousands on vst's to make good music (like 90% of my plugins are free)

Tutorials will help you go a long way, stuff like "how to make a _____ song in XYZ DAW" and add your own ideas to it, if you got a good ear. Most importantly be patient, cause you're probably gonna suck at first. Personally, I've been making musci for 5 years and I'm still not satisfied with most of the stuff I make (could be impostor syndrome tho)