For a tutorial, here is a simulation containing the chief components of a buck converter. It is animated and user-interactive (you press the momentary switch to operate the converter).
Electron flow (or rather current bundle flow) is portrayed according to direction and intensity. Scope traces tell the story.
It takes a minute of experimentation, to find the right tempo of switch-clicking, so that you create waveforms that are similar to your diagrams. You'll see how duty cycle affect output voltage. Below the diode waveform you might spot a frequency readout.
By clicking the link below:
1) Navigates to website
falstad.com/circuit
2) Loads the schematic.
3) Runs it on your computer.
tinyurl.com/y5xp27vj
It takes a minute of experimentation, to find the right tempo of switch-clicking, so that you create waveforms that are similar to your diagrams.
You can save the schematic to your computer.
You can edit it, change values, add components, etc.