I consider history always useful to enlarge the insight and therewith also appropriate to ease learning.
In this course I start with the Western music culture of the 17th century. Who has followed it before learning more modern things has laid a base in knowledge and feeling.
Jazz is founded on the meeting of different styles: Western music, the primal blues, the ragtime and the rhythm of the Latin-American son (with a rhythm that resembles the rumba) Earlier in this course I have discussed the primal blues, the ragtime and probably also the rumba. Certain notes were characteristic, like beside the blue note, the notes of the root chord of the relative key and the seventh notes of the chords.
The 12 measure chord scheme of the primal blues is used in the boogie-woogie. You have to feel like a machine in order to get the fascinating, strict, rhythm. Learn only a single left hand, as the touch of it determines the quality of the boogie-woogie. If you use several different left hands, you mistakenly search the variation in the melody, while it actually is about the rhythm.
The primal blues has developed in a different way by adding more chords. It is a meeting of the influence of the modulations of the classical Western culture and the primal blues. An example is the song 'Careless Love song' of which initially are limited to C C7 F Fm etc and where later on the chords A7 and D7 were added. It is still called a blues.
Together with the son and the rhythm of the ragtime the jazz developed to New Orleans or Dixieland. By improvising in the street it is logical that wind players are inclined to play polyphonically. Everyone has his own melody, but together they harmonize. The trick of this is to take the chords scheme of a song as a basis.
In a hall apart from wind players other instruments are used, like a piano and a guitar. The sounds cause the swing style.
The style of the big band has less improvisation and more composition elements.
After the second world war the style of the jazz is so different that there should be used another word for it. I don't like it as, in contrast to the original jazz it does not juice up (compare 'jazz up') but has an atmosphere which is called 'cool'. It also is less polyphonic (with harmonizing, different, melodies) but has more solo elements which is less complex.