The conclave is a secret session held in the Sistine Chapel in Rome with up to 120 cardinal electors. The conclave is closed off to the general public and each cardinal elector must take an oath of absolute secrecy about voting and deliberations before they enter the conclave. This is known as sequestration – kind of like how jurors in a jury trial may be sequestered. The penalty for disclosing anything about the conclave is automatic excommunication, i.e. kicked out the Catholic Church.

The cardinals take seats around the wall of the Sistine Chapel and receive ballots with the written words Eligo in summum pontificem – "I elect as supreme Pontiff…" Each cardinal prays and eventually writes a name on the ballot, folds it in half, and places it in a chalice. Cardinal Camerlengo counts the votes with his three assistants.

One Cardinal must receive at least two-thirds + 1 of the votes to become the new Pope. If one cardinal receives the required votes, a special chemical is used to burn the ballots to give off a white smoke that comes out of the Sistine Chapel. This signals to all the onlookers standing outside the Sistine Chapel that a new Pope has been elected. Additionally, the Vatican rings the bells of St. Peter’s Basilica to signal the new Pope so there is no confusion about the color of the smoke. If no cardinal receives the required votes, Cardinal Camerlengo burns the ballots with a different chemical to give off black smoke to signal that a new Pope has not been elected.

The cardinals vote on the afternoon of the first day, then twice in the morning and twice each afternoon for each subsequent day until they elect a new Pope. If they fail to elect a new Pope within the first three votes, then they may devote up to one day of prayer and discussion before resuming to vote. They may do this every 7 unsuccessful votes after that.

During the actual voting process the electoral cardinals must refrain from all contact with the outside world. A few select individuals perform regular sweeps of the Sistine Chapel for any types of listening devices. Each cardinal elector may also choose two or three attendants during the conclave to assist him. The workers and assistants at the Sistine Chapel are forbidden to talk to anyone during the electoral process.

No conclave in the last 200 years has lasted more than 5 days.

Next, we’ll go over who can become Pope.