Hello @Raul20,
There’s a pretty important step missing, from the very beginning of the simulation setup. The geometry currently consists of the solid parts of the room:
To run the simulation, you will need a single volume representing the flow region:
In short, you have to create the flow volume in CAD mode, and then delete the solid parts. This article provides more insights: How to Create Flow Volume Extraction? | Knowledge Base | SimScale
Cheers