How the current flows through the components in circuit?
The current flow through 3906 transistor collector to the base of the second transistor and the collector of the second transistor to disc capacitor to electrolytic capacitor to the horizontal trimmer resistor and the 220 k ohm resistor . Than to the second transistor 3904 and inverter transformer p. Than the current takes the way to the speaker
Explains the purpose/job of the different components?
The two transistor causes a feedback path. The second capacitor also helps sustain oscillations and the sound is controlled by the path of trimmer and the second resistor.