Why some of my walls got messed up when I deleted the room? and where are my objects go?

[@Marwa_AB]

OMG that helped me SOM MUCH, I was about to cry because my wall disappeared while I was adding windows and doors, and your video helped me som much I thank you million times🥹🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍