How to make a house?

I was wondering how I make a home in the following way: I want to create a scene where you see the house from the outside, then when you enter it, the game goes to another scene and you'll be inside the house.

To create the home, inside and out I only use Blender to create or inside the house I use Unity? Please explain to me the process of creating homes, because my game will move into a mansion.