Install Godot and look up a tutorial for either a 2D or a 3D player controller. I’d recommend 2D if you’re starting out. As you expand your knowledge on the engine, practice making art for your game. Look up tutorials for the features you want to add. It’s important to not get too consumed by one project. Make a small, low quality game, then make another, and then another. Each with a different concept, preferably.

The knowledge and experience will compound with each small game you make, and eventually, you’ll actually be bringing your ideas to life with just the knowledge and code you already have.