Udhiya (Layya or ileya) is a recommended Shariah act of the Prophet (peace be upon him) which originated from his father Ibraheem (Abraham) (peace be upon him).
Also, a single ram for instance can suffice a household (a man & his family), but two or more people cannot contribute money to buy a ram for this particular act of worship.
Again, the animal must be very healthy, not an emaciated one that looks sick & bonny.
It is an innovation in religion to keep any part of the meat for what we see in some parts of our communities, Takutaha celebration.
With regards to the Eid prayer, it consists of two rak'ahs. The first Rak'ah has 7 Takbeers while the second Rak'ah has 5 Takbeers.
With regard to the Takbeers of Eid, we are recommended to start such Takbeers from the morning of the Eid day. The Takbeers are:
ALLAHU AKBAR, ALLAHU AKBAR (continuously). Or ALLAHU AKBAR, ALLAHU AKBAR, LAA ILAAHA ILLAALLAHU, WALLAHU AKBAR,
All these Takbeers were not heard directly from the Prophet (SAW), rather from his companions & thus, while some do only the Takbeer, some add the Tahmeed (as written above in bold letters). So anyone we do, it is acceptable.
May Allah accept from us & from you.