Ask for one thing at a time — "add two windows on the left", "make it dark grey", "raise the eave to 20 feet".
Precise wall-local move and resize controls.
Turn on Edit, then select an opening in the model or from this list.
Drag the face to move, up onto the storey above included. Edge grips resize. Shift gives fine drag; Alt resizes from center; Delete removes.
This design has no ventilation to edit.
Opening editor off.