In the previous parsha, Vayikra, the laws of the types of offerings and the types of people who were to offer them was given. In this parsha, "Tzav", Moshe rabenu transmits the instructions for the priest's follow-up duties with these offerings.
The first aliyah gives the duties of the priest in connection with the burnt offering and the meal offering. The last line says that any food that comes in contact with the holy meal offering, itself becomes holy.
The commentaries say that this is because the thing that touched the holy object absorbed some of the taste of the holy object and that caused its holiness to be absorbed with the taste. This teaches that the mere taste of the food has the same status as the food itself. (This is why any food cooked with nonkosher food or even in a nonkosher pot, becomes itself nonkosher.)
The offering of the priests, themselves, is given in the second aliyah. An ordinary priest brings it only on the day that he is anointed, while a Kohane-Gadol (high priest) brings the offering of a priest every day. An interesting thing about the priest's offering is that all of it is burnt -- none of it is eaten.
The procedures for the sin offering and the guilt offering are also given here.
The third aliyah contains the procedures used in connection with the peace offerings.
We are told here to not eat the blood of any mammal or bird. This is why we, or the butcher, "processes" the meat with soaking and salting and rinsing to remove any blood before we can further prepare the meat.
In fourth aliyah, Moshe anoints Aharon and his sons to be the Kohane Gadol (high priest), and priests, respectively, and serve in the Mishkan (the tabernacle in the desert). Moshe assembles all the Jewish people and immerses Aharon and his sons in the mikvah. Then he dresses them in their priestly garments, and anoints the Mishkan and all its contents, as well as Aharon and his sons, with the holy anointing oil.
The fifth aliyah continues the description of the installation of Aharon and his sons as priests with the sacrifice of a bullock for a sin offering and a ram for a burnt offering.
Continuing the priest's installation, the sixth aliyah describes the procedure used for the installation offering: it consisted of sacrificing a second ram and placing some of the blood on certain parts of Aharon and his sons' bodies.
The seventh aliyah completes the process of installing the priests. Moshe anoints them with the holy anointing oil, and commands them to eat a special meal at the entrance of the tent of meeting. This installation ceremony lasted seven days.
