@icedquinn I always say the best way to learn digital music is to try to recreate something by ear. Don't use midis, don't look at the original chords, just remake it. You'll pick up on a lot of interesting techniques.

Also, it depends on what kind of music you're going for, but the way I generally write songs is that I start by labbing out the lyrics and melody with a ukulele IRL. write down the chords I use and just get those basic chords into the software with the default piano sound. Then I'll find some synth that sounds cool and replace the piano with it and sort of build around it. When I'm listening to that main synth chord progression I'll hum or kind of beatbox to it until I find something that sounds good and then translate that to new tracks. As soon as I get it sounding good, I'll set that up as my baseline and work from there, extending it, cutting it, replacing tracks or adding some for grander moments of the song, stripping them back when they aren't needed, etc.

As far as the lengths of loops go, it's pretty variable depending on what I think sounds good, but then I'll often smash 4 loops together and change them up a bit, so that it doesn't sound as loopy and there's a bit if variation there. You'll still want to do that minimally for most genres because it can be distracting if it's done too much unless you're specifically going for a more progressive or experimental sound.