Reaper DAW
I've been using Reaper, which is a DAW (Digital Audio Workstation) for music production. It's free and lightweight. A lot of people seem to like it and apparently it can do things just as well as the fancier-seeming DAWs. I think a lot of its potential is unlocked through plugins.
There's a set of videos on the Reaper website that is supposed to be good for learning some basics. I haven't really gone through it but I've watched a couple. I have a lot to learn.