Can I make a scene in Blender and import it into Unity?

Hi, I'm new in Unity. I had make a scene in Blender, and I want import it into unity. I don't know whether it works or not. So first, I export Blender into .fbx file, and put it into Unity scene. Second, create a collider to walk on the Blender, but after the collider walk two steps forward, it always pass through the Blender plane. I had search the internet, but didn't get any imformation about it. Or I just create the plane in unity, and the rest of the model use Blender to create?

Easiest just to create a plane in Unity.

I would not create an entire scene in Blender, but make all the parts in it and add it to Unity. So if you scene is, say, a house, and it has stairways, you could import this as one big mesh (good luck texturing it), but you'd have to use the same mesh as a mesh collider. Probably overkill. Generally you want to use simpler shapes as colliders.