I've been wanting to play around with synthetizers / trackers (?) for a bit. I played around with TIC-80 (another fantasy console like PICO-8) amazing track + SFX editor, but I'm very lost as to how to actually make... music, instead of noise.
Does anyone have any beginner resources on music theory, specifically oriented to working with synthetizers and trackers?
https://github.com/Dirtywave/M8HeadlessFirmware
You might also look at Pure Data and Max.
https://cycling74.com/products/max
In terms of actually making music, I think that probably just comes with both practice and experimentation.
These trackers are built around the limitation of old computers, some people prefer working that way because that's how they started but I wouldn't bother with them as a beginner nowadays. Some DAWs like reason try to emulate a real studio with cables and all, simmilar to this pico-8 app, but again, if you never worked in a real studio why would you bother?
The only "real" classical music theory you need to know is Scales, the bigger chunk will be knowledge about digital audio production. Synthesizers, compressors, filters, ... that information is also plenty available on youtube.
If you want lower-level stuff and program a synth manually, then you can try PureData, but it might be too low-level for you and require dealing with math equations and algorithms. Also, its GUI is a little outdated.
If you want to know how certain sounds are created, you can look for tutorials or Youtube videos. Or you can take any virtual synthesizer, choose the preset you like and see how it's made. You can disable units one by one and see how it changes the sound. For example, you can take Dexed or Surge, both of which are free.
Of course, beforehands you have to learn the basics (what kind of waves are there, what is a spectrum, an envelope, how filters work and so on).
Regarding music theory, I think that tracker or 8-bit music uses standard notes and chords and you don't need any special music theory for it. Also if you can hear the notes then it will help you a lot. A good ear is important because it helps you to hear what is wrong with the sound and how to fix it.
Also, a desktop DAW like Ableton (which is recommended by neighbour comment) might be easier to use than a tracker.
Also, you can listen to the melodies you like and reverse-engineer them, if they are available in a tracker or MIDI format.