Conclave is a term that comes from the two Latin words,

meaning with a key,

referes to the fact that the cardinals are locked behind closed doors while they go through a highly ceremonial process of casting ballots and then burning them, then it goes as long as it takes for someone to get two thirds,

the shortest conclave in history took a couple of hours, the longest one took three years.

In the old days, they would burn ballots, largely because they wanted to maintain the secrecy of the conclave, that is they didn't want the vote totals to get out.

What they realized is that when people saw the smoke from chimney atop the Sistine Chapel,

they knew a round of balloting had ended and so they came up with the system or they would put chemicals into the mix to turn the smoke black if no Pope had been elected, and white, if a Pope had been elected.

In theory according to the law of the church, any person who was eligible for ordination to the priesthood and therefore for an unmarried male, could be elected as Pope,

but in practice, a new Pope will be elected from among cardinals who are voting, that is the cardinals who are under the age of 80 who will take part in this election.

Which means that the roughly 150 cardinals aren't merely voters, they are all also candidates.

When a candidate cross that two thirds threshold, another cardinal will approach him and say,Do you accept your canonically valid election as Supreme Pontiff.

If he answers yes, from that moment forward, he becomes the Pope.

The next question is by what name will you be known.

And at that stage, the new Pope tells his brother cardinals what he wants to be called and then a few minutes later when the announcement was made from a balcony outside St.Peter's Square, the whole world will know the name of the new Pope.