Thanks for your input. I'll certainly look into Cakewalk. I looked into DAWs, but usually the tutorials that I found were about the paid, professional versions, which I don't think make sense to invest money in the beginning.
And I see what you mean on the "chaos". This was somehow the intention, but I guess it went far over of what I was looking into (I composed it in a piano as a harmony for the first melody, then transcripted and changed to several instruments, just joining some notes/adding some inessential notes just for bridging). Maybe keeping it simpler would have gone way better, looking in retrospective.
Again, thanks a lot for your constructive feedback. I'll look forward to change this melody in the future, making it simpler (and giving it time to rest, as the first feedback mentioned as well). All the best! :)