Let me see if I can explain this :
These are NOT the plans to the house extension (they are for the eviction studio).
These ARE the plans to the house extension. Going off assumption, drawing 1 appears to be the back of the building. Drawing 2 appears to be camera access/fire exits. I'm assuming that drawing 3 is where the new entrance doors will be. I'm also assuming that drawing 4 will be facing the new garden.