iTunes account

I had a Macbook Pro and used iTunes on it. Downloaded playlists from there to my iPhone and iPad. Good.

Now I have a Mac M2 Mini. iTunes does not appear to be on it. In Apple Music on the Mac Mini, I can see my old downloaded iTunes items and with difficulty some of them even play.

But how do I add a single new tune to my music downloads? I don't want and cannot afford a monthly subscription. I know you want to move me to a subscription system. Don't want that and I do want to be able to create new playlists with some of my previously downloaded iTunes together with newly downloaded tunes.

Thanks,