From Rabbi Reisman's shiur yesterday:
Tomorrow is Asara B’Teves, a fast day. Long Pshetlach are written about when Asara B’Teves has come on Friday. I'll give you the short version. When Asara B’Teves falls on Friday, two things are different. Number one, you don't say, Avinu Malkeinu by Mincha. Number two, you are allowed to take a hot shower. Normally, on a fast day, the Mishnah Berurah says, Ashkenazim have a Minhag not to take hot showers on a fast day. But on Erev Shabbos, you're allowed to. That's it. You don't need to read a five-page piece on Asara B’Teves She’chal B’Erev Shabbos. Everything else is the same. You break the fast the same time you would otherwise. You Daven first and make Kiddush at the Zman, whatever Zman you normally keep, for the end of a Yom HaTaanis.