Find out what "Jesus" did and then you will understand what they do....But I am sure you have no clue on how Jesus practiced his Judaism...
From what I have read, Jesus was a rabbi and an observant Jew who followed the minutae of Jewish law to the best of his ability, as observant Jews do to this day.
Since we have the Mishna, which dates back to the approximate time of Jesus, we have a pretty good idea of the Judaism that Jesus and other observant Jews practiced.