Every day boards are released for you to play. Those boards were played in Bridge Club Live in the past.
At the end of a hand you score is compared with 30 or more results for that same hand played in Bridge Club Live.
For example: If you, as N/S, score +620, the instant score shows you how many other N/S pairs also scored +620 and what overall percentage those pairs received for that score.
Your percentage will be the same percentage, less a small amount to take into account that one extra pair has now played the board.