Godot

My biggest piece of advice is to start small. This is extremely important in my eyes. When you're just starting out, you will almost certainly be super inefficient, writing code that'll cause you a ton of headache down the line. Prepare to abandon tons of projects. (I feel like this is something that gets said a lot, but no one actually pays attention to.)

A big help with this is starting with 2D projects. They are a whole lot simpler and they let you put more focus on things like learning how scenes and nodes work.

From there, you can read stuff like the GDScript reference page on the docs but ultimately the best way to learn is by doing.

My preferred way of learning things was to set my sights on adding some kind of feature, and then whenever I hit a wall, or I don't understand what something does, then I search it up. The docs are incredibly useful for learning about what different things do, and there are a lot of questions on ask.godotengine.org with answers that have been very useful to me.

There are also a few built-in script templates (at least in Godot 4). For example when you create a CharacterBody2D node you can get an example script for a basic platforming character. Although these came into existence after I learned the basics, I imagine analyzing them would prove very useful.