What do Jews do if Christmas day falls on a Saturday?

Answer 1

The question as written is confusing.

Religious Jews do not celebrate Christmas, so when it falls is completely irrelevant to any other extant Jewish celebration. Non-Religious Jews, some of whom celebrate Christmas in violation of Jewish beliefs on such, are usually not Shabbat-observant, so the restrictions of Shabbat that would directly interfere with Christmas preparations are irrelevant.

Answer 2

That's not a problem. Jews take essentially virtually no notice of Christmas Day
regardless of what day it happens on. The only exception is the Jew who typically
volunteers to work an extra shift on Christmas day so that one of his Christian
co-workers can spend the day with his family. If Christmas day happens to fall
on Saturday, the Jew would be less likely to make that offer.

Answer 3

Get Chinese take-out, same as any other year.

Answer 4

Christmas is a Christian religious occasion, not acknowledged or celebrated in Judaism.