How did you get the houses from the Quixel Medieval Village pack as single assets? In the project file they are make of like 20+ assets and organized by type of piece
once you load the project and start a new level you can find the house models from Content -> Maps -> HOLD. But it wont have the proper full texture, you can get more like the roofs , walls and others from Content -> Meshes . it will have more detailed assets which can add on to the house.