Do I play as single notes or octaves and does it matter what fingers I use for what?
Ron, welcome to your new addiction!
I'm also learning to play, although I have a two-row box. I'm several months along, but I come from a concertina background so the whole diatonic discipline isn't brand new for me. It'd help to know which style of music you're playing and which key the box is in, do you play other instruments, etc. I can offer the little that I've gleaned so far, but I'm confused by the way your question is worded.
- When you refer to single notes or octaves, it sounds as if you mean to play a tune by pressing two buttons simultaneously for the same note, in both octaves? If that's what you mean, the answer is a resounding no. You play the box in one octave at a time because otherwise you make extra work for yourself. If you try to do that, you'll quit in a week! I play that way sometimes on the concertina for exercise, but it's a two-handed affair. You play a melodeon more like a big harmonica. That's what it is, essentially. Later on you might play more than a single note at once for ornaments and chords (especially for Cajun music), but for now stick to one button at a time.
- Or are you referring to playing a tune one button at a time across two octaves, and you're having difficulty deciding in which octave to start the tune? If that's the question then I can tell what I do. I play almost everything in the high octave (the end of the keyboard closest the ground) because that's the octave which corresponds to where most tunes are played on a fiddle or bagpipes. But for the sake of my brain and fingers, I also learn everything that I play in the low octave. Once you're familiar with the instrument, learning tunes in both octaves is an intuitive process. They come naturally, and this is learning by ear. I think some tunes sound very nice in the lower octave, although there are some which require notes below the lowest note on the keyboard. It's fun for exercise, if nothing else.
- Regarding fingerings, there seems to be a "great debate" over whether a three or four finger style is preferable, and I think it all boils down to either who you learned from, your personal preference, the type of box you play, the style of music you play, or a combination of any of the above. Both sides have good arguments, and some points are specific to which style of music you're playing. Irish music tends to favor a three finger style, English four fingers; rather, players of the half-step system prefer three fingers and quint system (D/G, C/F, etc.) players lean toward four. I play a G/C and cross over the rows whenever useful, but I play with three fingers because it forces me to move quicker, I am more accurate, and my pinkie tends to linger and slow me down. I play cleaner phrases because rarely can I afford to keep two fingers depressing two buttons when shifting between notes, if you follow. But it you've got the little finger up to snuff, then it's all the same. I keep it "in reserve" and use it only in a pinch. Perhaps a one-row player on the site can give you better advice for fingering a one row.
Boxes are practical, fiddly things. If you're running out of fingers, then you need to change something: identify the problem, and make an adjustment. Repeat. A little like adjusting the floats on a carburetor, come to think of it.
I hope this helps you some. Good luck and have fun.