Salatul Janzah is a Fard Kafayah, that is, if one prays the prayer than all are free of the responsibility. Congregation is not a condition for this prayer, it is sufficient even if one person prays.
There is no Azan or Iqamah for Salat al Janaza which is offered with the participants standing and with the body of the deceased placed in front of them. There are no Rukus or Sujud to be performed in Salat al Janaza.
There are two parts of this Salah:
1) Four Takbiret - To say Allahu Akbar four times
2) Qayam - which was three Sunnat Mukeda: Sana, Durood Shareef, and Duaa for the deceased
Ibn majah 1/480, Ahmed 2/268
Allahummagh-fir lihayyina wamayyitina washahidina, wagha-ibina, wasagheerina wakabeerina, wathakarina wa-oong-saana. Allahumma man ahyaytahu minna fa-ahyihi alal-islam, waman tawaffaytahu minna fatawaffahu alal-eeman, allahumma la tahrimna ajrah, wala tudillana ba'dah
O Allah, forgive our living and our dead, those present and those absent, our young and our old, our males and our females. O Allah, whom amongst us You keep alive, then let such a life be upon Islam, and whom amongst us You take unto Yourself, then let such a death be upon faith. O Allah, do not deprive us of his reward and do not let us stray after him
Abu Hurairah (r.a) says that he heard the Messenger of Allah (s.a.w) said, " He who goes out with the bier when taken out from its residence and offers prayer for it and he then follows it till it is buried, he would have two Qirats of reward, each Qirats being equivalent to Uhud, and he who after having offered prayer (directly) came back would have his reward (as great) as Uhud.
As-salam-u-alay-koom wa rahmatullah
May the peace and mercy of Allah be with you