Shipibo ceremonies are held in the evening, starting when it gets dark and ending when the shaman feels his work is done, depending on the energies in the room and how much individual work he has on each participant.

At the beginning of the ceremony everyone takes their turn going to the shaman and drinking their cup of Ayahuasca, for those who are participating in a ceremony for their first time, the dosage will be adjusted. After that everyone takes their place, the lights are turned off and the shaman waits for about an hour before he starts to sing his icaros (songs). This hour is necessary for the Ayahuasca to start working.

When the shaman has finished singing his songs for general purpose, he begins to work on everyone individually. These individual treatments consist of singing personal icaros, at the end of singing to you, he will ask for your hands and to bow your head to blow tobacco smoke on them and/or rub them with agua florida (a kind of perfume).

Smoking pure tobacco (mapacho) is allowed during ceremonies. The shaman will also smoke mapacho in cigarettes or a pipe, the Shipibo use the tobacco to call the good spirits, expel the bad ones and protect the space. The tobacco plant is a sacred plant to the shamans and according to them the tobacco works as a bridge to the spiritworld of the Ayahuasca.
Some people (even non-smokers) like smoking the mapacho cigarettes during ceremony.

It is recommended not to eat anything anymore after lunch and stop drinking about 2 hours before the ceremony starts.
Bring a bottle of water with you to ceremony though, you might want to rinse your mouth after drinking the Ayahuasca, but don’t swallow the water at that time.Ayahuasca tends to continue working in your mind and body after ceremony ends, so the advice is not to drink a lot of water right after ceremony, as it is too heavy on the stomach.

On ceremony days there will be no dinner, on arrival day it’s best if you had a good warm lunch before you travel to the venue.

Before, during and after the ceremony one is expected to refrain from loud talking, singing or other noises. It can be very disturbing to other participants, before ceremony some people like to meditate or do yoga to prepare themselves for ceremony. During and after ceremony loud noises can even abruptly end the journey someone is experiencing, for some the effects of Ayahuasca happen to last longer than for others.

Only if necessary, there is a group meeting the day after ceremony to share experiences and consult the shaman. It is not mandatory to be at the meeting and share your experiences on the spot with the rest of the group. Personally I do not see much benefit from group meetings, the experiences you had during ceremony can be taken out of context when sharing them with a group. Everyone has their own emotional reference to things and that can cloud the lessons and visions that are your personal experience to work on and integrate in your daily life.
Of course you are more than welcome to individually share your experiences and ask questions about it.