The Unity NavMesh is a tool for implementing efficient pathfinding, enabling AI agents to navigate complex environments, avoiding obstacles along the way.

In this tutorial, you'll set up the NavMesh for your scene.

Start by selecting the scene geometry where you want the enemy to be able to walk.

In this case, you'll select the Ground Game object. 

With the ground selected, in the Inspector, select Add Component.

In the Add Component menu, search for and select NavMesh Surface.

The NavMesh Surface component represents the walkable area for a NavMesh agent.

Select Bake in the NavMesh Surface component.

This will initiate the process of generating the NavMesh based on the scene geometry and the specified settings.

After the baking process is complete, the NavMesh will be displayed in the scene as a blue overlay.

But there's a problem.

The pickups are currently being factored into the NavMesh with the enemy either going around them or walking over them.

For this game, we want the enemy to ignore these pickup objects entirely.

In the Inspector, in the NavMesh Surface Component settings, locate the Object Collection section.

Set the Collection Objects dropdown to Current Object Hierarchy.

This ensures that the NavMesh only takes the ground object and any of its child objects into consideration, and therefore ignores the pickup objects when baking the mesh.

Select the Bake button again. 

The pickup collectibles are now ignored in the NavMesh You now have the NavMesh setup for your scene.

The enemy won't navigate on it yet, though.

You'll do that next.