Initial Setup

Basic initial setup for a godot 3d game in godot 4.3 is as follows.

Set up a basic scene (no multiplayer yet)

Player:

We add a main scene in which everything will be happening.

Create a new scene "player", change root node to CharacterBody3D to start making a very basic player. add a script to it - the script already contains movement controls, but it uses the arrow keys or controllers rather than WASD.

add a collisionShape3D node to it, and to that add MeshInstance3D. select a CapsuleShape for the CollisionShape and a CapsuleMesh for the MeshInstance3D. This gives our player collision, and makes it visible in the game scene.

also add a Camera3D to the player scene, and move it away from the player a bit so you can see it moving around.

Game World:

in the main scene, we will add a node3d "objects" or similar, to fill it with some objects to move around on.

add a StaticBody3D, and to that node add a CollisionShape3D and a MeshInstance3D. select box shape for both. 

Copy this. One of them will be the floor (rename the node) and the other will be a random box we put in the world. Move the floor, and change it's Transform -> Scale to be much bigger, so we can use it as floor. move the box to somewhere on the floor.