[Malcolm]

Here is how you use your Major scale:

The director says; "The next song will be "Go kiss old Sallie" we'll do it in G and Derlan7 will take a lead break after the first chorus. Ready 1 & 2 & 3....."

From that you know that the rhythm section will use chords from the Major key of G, the vocalist will be using melody notes from the G Major scale (singing in the key of G) and when you take your lead break you will use notes from the G Major scale for the melody.

Ditto the Major scale being the foundation of everything we do, for example here are some of the things you can do with the C Major scale:

The C Major scale will use the 1, 2, 3, 4, 5, 6, 7 notes of the C major scale, i.e. C, D, E, F, G, A, B, C.
The C minor scale will use the 1, 2, b3, 4, 5, b6, b7 notes of that C major scale. i.e. C, D, Eb, F, G, Ab, Bb
The C Major pentatonic scale will use the 1, 2, 3, 5, 6 notes of the C major scale - you take it from here - that fish thing.
The C minor pentatonic scale will use the 1, b3, 4, 5, b7 notes of the C major scale.
The C Blues scale will use the 1, b3, 4, #4, 5, b7 notes of the C major scale.
The C Major chord will use the 1, 3, 5 notes of the C Major scale for it's makeup.
The Cm chord will use the 1, b3, 5 notes of the C Major scale for it's makeup.
The C7 chord will use the 1, 3, 5, b7 notes of the C major scale for it's makeup. And of course it goes on and on.....

Everything revolves around the major scale. It's the Rosetta stone for everything we do.