We strongly recommend this tutorial published in the Zenva GameDev Academy (and written by us ;-) ). It covers the steps to make a platformer game with the visual scene editor. It includes the source code created in each section and a final demo.
The tutorial is divided in sections like the project setup, assets loading, scene creation, physics setup, player controls, etc...
We specially like how to setup the physics of the level, by using an invisible collision group.