Instead of stairs I will make ramps, you can use CSGBoxes to make stairs if you wish.
By adding a container for
Level components as a Node3D
Rename it to LevelContents
Put the contents inside it
As a child of LevelContents
It's currently a cube but we want a pyramid
Expand the Polygon property
Set the size property to 3
Now Scale and Rotate the Ramp
Move it to the next location
Drag and drop the Player scene
You can now explore your level
Add a Node3D as a child of MainLevel
Drag into it some Enemy scenes
Place the enemies around the map
Add a Node3D as a child of MainLevel
Drag into it some Pickup scenes
Place the pickups around the map
Add a NavigationRegion3D as a child of MainLevel
Make LevelContents Node a child of NavigationRegion
Select the NavigationRegion3D node
In the Navigation Mesh property
Select the NavigationRegion3D Node
In the Viewport select Bake NavigationMesh
Now Enemies can navigate the level
Grab the new enemy model alongside
Delete the two MeshInstances
Select the AnimationPlayer node
Set the Animation to Autoplay
Set the Animation to Loop
At 0.0 Key the starting pos of the drone
At 0.5 Key move the drone up
Or down by 0.1 and Key it
At 1.0 move drone back to starting pos
Select the Attack Animation
At 0.0 Key the starting position
At 1.0 Key Starting pos and scale
Move the Attack function call to 0.1
Select the NavigationRegion3D
Expand the NavigationMesh property
Expand the Filters property