Chapter 102 – Eruv Tavshilin (the preparation of cooked food prior to a Jewish holiday that will be followed by Shabbat)
102.1) On a festival on a Friday, do not bake or cook in a separate pot for the Sabbath without performing an Eruv Tavshilin (the preparation of cooked food prior to a Jewish holiday that will be followed by Shabbat).
102.2) The food used for the Eruv must be one generally eaten with bread, like fish, meat, or eggs.
102.3) The Eruv tavshilin is only effective if done early in the day.
102.4) On Friday, food may be baked or cooked for the Sabbath by means of the Eruv tavshilin.
102.5) To be valid the Eruv must remain intact until the Sabbath necessities are taken care of.
102.6) Every household must make its own Eruv tavshilin.
102.7) If you forget to make the Eruv tavshilin on the Thursday of a two-day festival, you can fix this. See the source for details.