I can provide information regarding conclaves and the election of a new Pope based on the Apostolic Constitution Universi Dominici Gregis.

Here's what happens during a conclave to elect a new Pope:

General Information

• Exclusivity of Location The election of the Pope is to take place exclusively in the Sistine Chapel in the Vatican 1. The Sistine Chapel is to remain an enclosed area to ensure total secrecy regarding anything said or done pertaining to the election 1.
• Regulation of Vatican City During the electoral process, the territory of Vatican City is regulated to permit the election to be carried out with privacy and freedom 2.
• Secrecy The Cardinal electors promise and swear to observe the greatest fidelity and secrecy with all persons, clerical or lay, regarding everything that relates to the election 3. The oath includes maintaining secrecy about what occurs in the place of the election, directly or indirectly related to the results of the voting 3. This oath is taken by each Cardinal elector 3.
• Oath In the first General Congregations, each Cardinal must have a copy of the Universi Dominici Gregis and have the opportunity to ask questions about it 4. The part of the Constitution regarding the vacancy of the Apostolic See is read aloud, and the Cardinals present swear an oath to observe the prescriptions and maintain secrecy 4.
• Checks for technology Careful and stringent checks must be made to ensure that no audiovisual equipment has been secretly installed in these areas for recording and transmission to the outside 1.

Participants

• Cardinal Electors All Cardinal electors, convoked for the election of the new Pope by the Cardinal Dean, are required to obey the announcement of convocation and proceed to the place designated for this purpose, unless hindered by sickness or some other grave impediment approved by the College of Cardinals 5.
• Essential Qualities Cardinal electors must be legitimately appointed, have the use of reason, and be present in person, not through a procurator or by letter to vote in the conclave 6. This right is acknowledged even if they are subject to ecclesiastical censures (e.g., excommunication), or if the solemn ceremonies of their "creation" have yet to be performed 6.
• Cardinal Dean The Dean of the College presides over the General Congregations of Cardinals in the Apostolic Palace in the Vatican 7. If the Dean is absent or impeded, the Subdean presides 7. If both do not have the right to elect the Pope, the senior Cardinal elector presides 7.
• Ineligibility According to No. 33 of this Constitution, if the Dean or Subdean no longer enjoy the right of electing the Pope, the assembly of Cardinal electors will be presided over by the senior Cardinal elector, according to the customary order of precedence 7.
• Those Admitted The Conclave for the election of the Supreme Pontiff takes place within the territory of Vatican City, in determined areas and buildings, closed to unauthorized persons to ensure suitable accommodation for the Cardinal electors and all those legitimately called to cooperate in the orderly functioning of the election 8.
• Conclavists Each cardinal has a right to take into the conclave a secretary and a servant, the secretary being usually an ecclesiastic 6. In case of illness a third conclavist may be allowed, with agreement of the general congregation 6. All are equally sworn to secrecy and also not to hinder the election 6.

Process

• Beginning of Election The Cardinal Dean asks the College of electors whether the election can begin, or whether there still remain doubts which need to be clarified concerning the norms and procedures 9.
• No Changes It is not permitted to modify or replace any of the norms and procedures which are a substantial part of the election process, even if the electors are unanimously agreed, under penalty of the nullity of the same deliberation 9.
• Ballot Papers The ballot paper must be rectangular and bear the words "Eligo in Summum Pontificem" in the upper half 10. The lower half must have a space for writing the name of the person chosen 10. The ballot is made to be folded in two 10.
• Completing the Ballot The completion of the ballot must be done in secret by each Cardinal elector, who will write down legibly the name of the person he chooses, taking care not to write other names as well, since this would make the ballot null 10. He will then fold the ballot twice 10.
• Voting During the voting, the Cardinal electors are to remain alone in the Sistine Chapel 10. Immediately after the distribution of the ballots and before the electors begin to write, the Secretary of the College of Cardinals, the Master of Papal Liturgical Celebrations, and the Masters of Ceremonies must leave the Chapel 10. The junior Cardinal Deacon shall close the door, opening and closing it again each time this is necessary, such as when the Infirmarii go to collect the votes of the sick and when they return to the Chapel 10.
• No election by compromise The election per compromissum was eliminated because it tends to lessen the responsibility of the individual electors who would not be required to express their choice personally 11. The only form by which the electors can manifest their vote in the election of the Roman Pontiff is by secret ballot 11. This offers the greatest guarantee of clarity, straightforwardness, simplicity, openness, and an effective and fruitful participation on the part of the Cardinals 11.

Responsibilities During Vacancy

• Limited Power During the vacancy of the Apostolic See, the government of the Church is entrusted to the College of Cardinals solely for the dispatch of ordinary business and of matters which cannot be postponed, and for the preparation of everything necessary for the election of the new Pope 12.
• Excluded Matters Those matters are to be absolutely excluded which, whether by law or by practice, come under the power of the Roman Pontiff alone or concern the norms for the election of the new Pope 12.
• Dicastery Heads At the death of the Pope, all the heads of the Dicasteries of the Roman Curia cease to exercise their office, except for the Camerlengo of Holy Roman Church and the Major Penitentiary, who continue to exercise their ordinary functions, submitting to the College of Cardinals matters that would have had to be referred to the Supreme Pontiff 13.

In summary, the conclave is a complex process with strict rules and procedures to ensure the proper election of the Pope. The Universi Dominici Gregis outlines these regulations, emphasizing the importance of secrecy, individual responsibility, and prayerful discernment by the College of Cardinals.