Translation:Shulchan Aruch/Orach Chaim/429
1. We learn the halakhot of Pesach from 30 days before Pesach. RAMA: And it is customary to buy wheat to give to the poor for Pesach. And whoever is residing in the city for twelve months must give for this (Or Zarua).
2. We do not say Tachanun through the entire month of Nissan, and we do not say "Your righteousness" on Shabbat at Minchah, and we do not deliver eulogies, and we do not fast for communal needs, and the first born fast on the eve of Passover. RAMA: And we do not say [the funeral prayer of] Tziduk HaDin during the whole month of Nisan. And the custom is that there is no fasts at all, even on the day that a person's parent has died. But one does fast for a bad dream. And on the day before Passover we do not say Mizmor LeTodah (Ps. 100), nor Kel Erech Apayim, nor Lamenatzeach (Ps. 20). This is also the case on any Festival. And it is customary to eat and drink a little more on the day after the Festival, which is Isru Chag. Gemara and Rashi Perek Lulav