This is not an easy question! Let’s start with what C means. C means that is the key the piece is being played in. Looking at a piano is probably the easiest to understand this. On a piano keyboard each of the keys has a letter designation. In the middle of the keyboard there is a spot you can see where there is a section that you have keys going (from L to R) white-black-white-black-white-black-white-white-black-white-black-white. Each key going up is a half step. That doubled up white keys are B and C. So in a key of C major you would start on C and go up in a series of steps W-W-H-W-W-W-H (W = whole step or 2 keys regardless of color, H = half step or one key regardless of color). So C major would be all the white keys going up…no black keys. These notes would be C-D-E-F-G-A-B. C minor follows a different series, W-H-W-W-H-W-W, meaning you would be hitting some of the black keys.
For other keys you would start on whatever key it is and follow the same series of steps going up. The key of D would start at D and follow the same series going up. Of course going down too, but the series is reversed.
Major keys tend to have more upbeat sounds, happier sounds, minor keys tend to have more melancholy sounds.
On sheet music, the “sharps” or “flats” are shown, meaning these are the ones that are going to be the black keys. In this example we see on the left side of the lines several things On the top series, we see what looks like a cursive G symbol. This is the treble clef. On the lines below it there is something that looks like a spiral C. This is the bass clef. You sometimes see this as a C with 2 dots next to it. The next thing you see next to the clef symbols is a group of what look like lower case “b“s. These are the symbols denoting the notes in this key that are going to be “flats” In other words the notes that fall on those lines are going to be played flat, or half a step less than the normal white key on a piano. I’m a bit rusty but I believe 4 flats is the key of A-flat major. Starting at A-flat you would follow the same series of whole and half notes going up, regardless of color.
Now, those “flat” symbols sit on lines or spaces. Yep, each line and space is a different note. If you look at the Treble clef (the upper series of lines) the bottom line is E, but it is specifically the E above Middle C (the C in the middle of the keyboard). The space above E is F, the next line up is G, the next space is A, and so on. But if the bottom line is E, where is Middle C? Well, on the sheet music example I gave, if you look a couple blocks (or stanzas) to the right you see an odd note hanging down below the lines and it has a line through it. This line denotes the next line going down in the series. So counting down from the E at the bottom of the lines, the next space would be D (just below the line) and then this weird note with a line through it would be the next line down or C. On the bass clef, the top line is A, the next space down is G (notes only go A-G), the next line down is F and so on. It should be noted that the lines and spaces don’t get called different things based on what key the music is in. They are based on the C scale on a piano – All White Keys. The key indicator (the flat notes next to the clef symbols) are the reminder that every time one of those notes is shown in the music it is to be played half a step below that white key.
The sheet music I gave has flats shown. They look like a small case “B”. There are also “sharp” symbols that look like little tic-tac-toe boards. When you see these you play these notes half a step above the white key.
