1. The Mishnah says that about ten booths were set up between the cliff and Yerushalayim.
2. The person taking the goat was escorted by others from one booth to the next booth.
3. After pushing the Se'ir la'Azazel off the cliff, the person escorting the goat would rest in the last booth until the end of the fast.
4. There is a dispute about the point at which the person who pushes the goat off the cliff becomes Tamei.
5. There is a dispute in the Gemara about how many booths there were.
A BIT MORE
1. These booths had food and drink for the person bringing the Se'ir la'Azazel to the cliff. The reason for these provisions was to give the person reassurance that if he needed, he could eat or drink, but not that he actually should break his fast.
2. The people from one booth would escort him to the next booth; the people from that booth would escort him to the next, and so on. The people in the last booth would escort him until the end of their Techum and watch as he pushed the goat off the cliff.
3. Despite the food and drink that was offered, the person escorting the Se'ir la'Azazel never broke his fast.
4. Tana Kama: He becomes Tamei right after he starts escorting it out of Yerushalayim. Rebbi Shimon: He becomes Tamei only after he pushes the goat off the cliff.
5. Some say that there were nine, and some say there were five. Technically, an Eruv Techumin could have been made so that fewer booths would be necessary.