I play Acoustic Guitar & Harmonica as well. Recently, I have started using DAWs for composing my own tunes. Fruity Loop & Magix Music Maker are the two DAWs I use. These DAWs have built-in Piano Roll, using which we can compose tunes. I know how to play a C-Major, G-Major or any other code in a real acoustic guitar & harmonica. I want to play these notes in the DAW. All I see in front of me is a keyboard. I hope for some help.