Hey, I’m not sure what center of a room means here because rooms can have various shapes so it might be harder to compute the center. But what you can do is, for example, get all the floor tiles that are in the room and you can spawn something on them. If you wanted to do that, you’d have to create a post-processing task which gets an instance of the generated level. From there, you can get a list of all the rooms in the level (represented by the RoomInstanceGrid2D class). Inside that, you have the RoomTemplateInstance property which is a reference to the prefab from which the room was made. There you can find the Floor tilemap and get all the tiles inside it. You can use these floor tile positions as a base for your spawn behaviour.
Does that help?