What you want to do is actually quite advanced topic. Godot is coming with some build in functionality that you can use Look for navigation mesh

But if you never used a game engine I recommend you start with baby steps and lern how Godot works basically. Try to create a scene, create an object, add a script and try to move it from code… All this stuff.

I would recommend to at least completely the getting started section of the Godot docs this should give a very good overview.

Regarding 3d models, you can:

• use spheres and cubes as placeholders, there is no need to create 3d models as long as you don’t have a game yet.
• you can download models for free from various websites
• you can make your own 3d models with blender ( If you don’t know how to do that yet, you will have to spend some time learning about blender first. Checkout blenderguru)

Since you ask for the easiest solution, just use CSGMeshes for your maze and a cube or sphere mesh for your enemies.

Yeah, for an enemy you can find a model online, use a basic cube or cylinder, or make a model in Blender. Using Blender is pretty complicated so I would use some other model or a basic shape while you get started, you can always make one later. Then for enemy navigation you can use the built-in navigation system.

However, if this is your first time making a game, I would work on the first person controls before tackling navigation or modeling. For your first game you pretty much need to follow a tutorial to learn how to use Godot, so I’d find a tutorial like this one on how to make a first-person game. It could also be helpful to follow a basic tutorial like this one just to learn how Godot works. Learning how to make games is pretty difficult so don’t worry if it takes you a while to get things working, especially if you don’t have any programming experience.

As others have said so far. If you have zero experience what you are aiming for is pretty complicated.

• you need path-finding. Godot nav mesh will do great. But you could implement waypoints and A* yourself if you like more control and want to learn.
• you need some place holder models. Using prisms or Sprite3d is better because you can more easily see which way they are facing
• you need some agent behaviour. What does move randomly but also towards the player mean? Are you thinking of a pacman like situation?. You might want to think about a state machines
• If you want the levels to be procedurally generated you open a whole new can of worms.
• Depending on your use case you might want to spend time getting comfortable with the UI framework and Control nodes to create buttons and widgets to create start and reset levels.