Instead of playing music performed and produced by others on your computer or phone, that is.
Ideally it's just a word, but a phrase works too. Ideally it also includes the concept of songwriting, but it doesn't need to. It should apply even if playing is not done in front of other people or ever recorded and shared with other people.
Currently I say "I like singing, playing guitar and piano, and writing music." But it's a mouthful and way more specific that I mean to be. I've also used "I'm an amateur musician", though that seems to imply I share my work with others (by performing or publishing online or in person), so I don't think it would have applied before I started doing so.
This is similar to Word for "to make music" except this question doesn't require a single word, so hopefully we can find some more natural and clear phrases than the single words "jam" (which implies improvising with others), "melodize" (which sounds unnatural in casual conversation, and confusingly seems to imply something about working on melodies specifically, like "harmonize"), or "perform" (which implies doing it in front of others).