Jazz up sample scene 'CanvasShadow'

[Species521]

Describe the problem

The scene might be a little hard to read for new users, also it is generally not much to look at and the documentation is missing

Describe the solution you'd like

Cleaning up the scene, apply descriptive panels and add a doc.

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

Add any other context or screenshots about the feature request here.