Click on the Scene Menu and choose New Scene 
Press CTRL+S - Name the scene TestScene3D 
To navigate the 3D environment, use the following controls: 
Hold the right-mouse button to look around the scene 
Use the W A S D keys to fly around the scene 
Use the middle mouse to orbit around the center of what is on the screen. 
In 2D Godot, we use Sprites 
In 3D we use a Mesh Instance 
Add a new MeshInstance3D node 
This 3D Cube can be moved, rotated and scaled using our tools. 
Note that in 2D units are measured in Pixels. 
In 3D units are measured in meters.