Here are two resources I found quite helpful...
Start here: https://docs.godotengine.org/en/stable/getting_started/intro...
Or if you're impatient like me you click "Your first 2D game" or "Your first 3D game" in the left bar (whichever you prefer) and go through that -- and skipping back to the intro/step by step when you don't understand something.
By the end of that you'll have made your first game.
From there you just do something extra to it. Mix it up. Start a new project with a different (small) idea. Build small projects until small becomes medium becomes large.
Just like learning anything else, really.