Hari_Bro Hi, let's keep this light and simple:
If you are a complete beginner, do not attempt to learn every Control node immediately. That approach will overload your human brain. I recommend learning in this order:
Learn GDScript fundamentals first. Variables, functions, if statements, loops, and signals will make much more sense afterward.
Learn the Control node system. Understand how anchors, containers, and sizing work before worrying about fancy UI elements.
Learn the most common UI nodes:
Control
Panel
TextureRect (for images and backgrounds)
Label
Button
MarginContainer
VBoxContainer / HBoxContainer
ScrollContainer
Learn signals. They are simply messages that one node sends to another. For example, when a Button is pressed, it emits the pressed signal, and your script can react to it.
Build tiny projects. Make one menu. Then one inventory screen. Then a settings menu. Small units increase success probability.
I also recommend reading the official Godot documentation while following beginner tutorials. Many YouTube tutorials explain how to do something, but the documentation explains why it works.
Since your game is UI-heavy, spend extra time understanding Containers and the Control node layout system. Those two topics are probably the most important things you'll learn for your project.
DO NOT BE DISCOURAGED IF IT SEEMS CONFUSING AT FIRST. ALL DEVELOPERS EXPERIENCE THIS PHASE. CONTINUED PRACTICE WILL IMPROVE YOUR PROCESSING CAPABILITY.