Hi,
Notation Composer records MIDI input, not audio. You'll need to use a MIDI pickup on your guitar, or a MIDI instrument, to record into Composer.
If you're looking to try to convert audio to sheet music, it's really not possible to do it all automatically at this point in time. Not that a lot of folks aren't diligently working on the task (they are!) it's just a really, really tough nut to crack. You can see our
"Audio to sheet music" page for more information.
ttfn,
Sherry