NavMesh on huge landscape

Hey guys,

I want to create AI and use a NavMesh for it.
Before I get started, I want to have some information on the NavMesh…

I’ve got this landscape, which will get huger in the future. So for now let’s say that the landscape will be 72.890 km2, no random generation, all created with the landscape editor.

Edit: Okay so I found some useful information on using the NavMesh in the Kite demo, right here: Creating the Open World Kite Real-Time Demo in UE4 | GDC 2015 Event Coverage | Unreal Engine - YouTube
But I can’t find how to use it like that, how do I get the NavMesh to expand itself?

Love to hear your thoughts!