Below/above stairs British old-fashioned
(Below stairs) at or in the basement of a mansion, deemed as the area where the servant worked and lived.
This story gives me insights into the life below stairs at Buckingham Palace.
The rich kid wants to experience the life below stairs.
(Above stairs) on the upper floor of a mansion, deemed as the area where the owner of the house and his/her family resided.
The son of the servant asked him what the life above stairs looks like.
The servant is feeding the cat that belongs to the people who live above stairs.
The origin of this phrase is not clear.
To be thankful or grateful for one's good luck usually while avoiding a bad situation
You should count your lucky stars as you managed to avoid that violent car accident.