He would have celebrated it in much the same way that Jews do today. Jews would go up to Jerusalem, and have a meal. Christian communion is a celebration of "The last supper" (an event which occurred at Passover ~ Easter is a lunar festival which occurs at Jewish Passover every year).
Many Jews suggest that the Passover celebration as reported in the New Testament in the upper room was little more than a Seder meal, with bitter herbs, special breads, prayers and songs.
At this meal, the New Testament tells that Jesus took the elements of this meal, bread and wine, and instituted a new ritual for his followers to remember him.