tar400

I have always played contract bridge and most people on BBO use IMP Scoring. I have looked on the internet for help but am certainly confused. Example: Contract is 4 spades and the score is 620. How did you come up with 620? Then there is a conversion to IMP. I can probably figure out the conversion (maybe lol) if I see how 620 is made. Thanks. I have no idea how to check back and see if anyone answers this. New to BBO Thank you!