I have a similar tuner a KORG GA-30, and I was making the same mistakes you probably are. I kept wondering why it wouldn't pick up any of the notes or was showing the wrong notes all the time. It was only until a friend of mine showed me how to do it. I had to tune it with "one flat" selected, then just pick the open strings starting from the thickest to the thinnest. Piece of cake, it's also super easy to tune by ear using the 5 fret method if you have a reference tone for the low E string.