Level Management in Unity, by Wilmer Lin (Link)
This course help me quite a lot in the Laser Droplets game. Not only I learnt a lot of coding stuff, the base code for the menus management is all from this course. Well, I did change and added some extra stuff here and there. For example I added the ability to navigate all the menus using keyboard and controller. The graphics are also replaced with another asset in the Unity Store.
All in all, I am very happy and lucky that I found this course.