Men, women, and children must hear the Megillah on Purim night and again on Purim day. At night it should be read after tzeit hakochavim - stars appear - and in the morning after neitz hachamah - sunrise.
Preferably it should be read in a shul and in the presence of a minyan of ten men, so that it will accomplish pirsumei nisa - publicizing of the miracle - and also so that it will be in accordance with the principle "Berov am hadrat melech" - "In the multitude of people is the King's glory" (Proverbs 14:28).
Before the reading of the Megillah the reader opens his Megillah in the manner of a letter and three berachot are recited . He should have the intent of fulfilling the obligation for the congregation for the berachot and the reading. The listeners should have the intent to fulfill their obligation.
The Chabad custom is that the reader and the listeners open their Megillah in the manner of a letter (folded three times) before the berachot are recited.
Everyone should listen carefully to the berachot and not interrupt by answering "Baruch Hu ubaruch Shemo." One should simply answer "Amein" at the conclusion of each berachah.
The reader must stand while reciting the berachot and reading the Megillah in public. The listeners may sit. However, when the berachot are recited, all must stand.
It is forbidden to make an interruption until the conclusion of the blessing which is recited after the reading. If the reader or the listener misses one word, he does not fulfill his obligation, and the reader must return to the word missed.
Unless the listener is holding a kosher Megillah, he should not read along with the reader.
During the reading, when the name of Haman is mentioned, it is customary to "bang" or stamp with the feet, etc. In Chabad this is done only when his name is accompanied by a description such as "Agagi" etc. The reader should stop and not resume till absolute quiet prevails.
It is customary for the entire congregation to read four verses aloud: "Ish Yehudi" (2:5), "U'Mordechai yatza" (8:15), "LaYehudim..." (8:16), and "Ki Mordechai..." (10:3). Afterward the reader repeats them.
The names of Haman's ten sons (9:7-9) should be read in one breath. This includes the preceding words, "Chameish mei'ot ish," and the following word "aseret."
The Chabad custom is that this is also read by the listeners first, with one breath .
The phrase, "Laharog ule'abeid" (8:11) should be reread as "Velaharog Ule'abeid." Similarly, the phrase "Ve'ish lo amad bifeneihem" (9:2) should be reread as "Ve'ish lo amad Lifeneihem."
When the reader pronounces the phrases, "Ha'iggeret hazot" - "this letter" (9:26), and "Iggeret haPurim hazot" - "this Purim letter" (9:29) the Megillah should be shaken.
After the reading of the Megillah, the berachah, "Harav et riveinu" is recited.
There are different customs as to whether only the reader recites the berachah or whether the listeners also do so, and whether the rolling up of the Megillah is done before the berachah or afterwards, and if the berachah is recited only when the Megillah is read in public.
The Chabad custom is that the berachah is recited only by the reader. It is recited before the Megillah is rolled up and only when the Megillah is read in public (with a quorum of ten men).
Afterward all recite, "Asher heini," followed by "Shoshanat Yaakov." Chabad custom is to say only "Shoshanat Yaakov."
All the details regarding the Megillah reading apply equally at night and during the day, except that when it is read during the day, during Shacharit, the Rashi tefillin are worn and "Asher heini" is not recited.
During the day when the berachah of "Shehechiyanu" is recited, everyone should also have in mind the mitzvot of mishlo'ach manot - sending portions of edibles to friends - matanot le'evyonim - gifts to the poor - and the se'udah - festive meal.