Scales, chords and formulas, oh no !  Don't worry ...the diatonic scale is the only scale you really need  to learn. Practically everything composed in Western music is built from and depends entirely upon the diatonic scale. You probably already know this scale and just don't realize it yet. Do you remember Do, Re, Mi, Fa, Sol, La, Ti, Do ?   You should memorize and learn how to hum or sing the diatonic scale.

The formula to construct a diatonic scale is as follows :  whole step,  whole-step, half-step, whole-step, whole-step, whole-step, half-step. Each fret  on the guitar equals a half-step. Therefore, 2 frets   on the guitar equals a whole-step. The diatonic scale is built from the chromatic   scale. The chromatic scale is simply the root(1st) tone followed by each half-step tone ascending consecutively until arriving at the root(1st) tone one octave higher in pitch.

Practice building diatonic scales from each tone in in the musical alphabet starting with "C". I've already built the C diatonic scale from the example shown above so use it to help you with your assignment. (*hint) Note there are no half-steps between B/C and E/F ... ever !  To show you how easy it is I'll build one more diatonic scale starting with the D tone.

Build some diatonic scales on your own now. You'll have done it correctly if there is a half-step between the 4th/5th and 7th/8th tones. Yes, there are flats but just use all sharps for now ...we'll get to the flats later.