So how do they choose the Pope? Since a Pope hasn't abdicated since the 1400's this will be a new experience for all of us.
And how do they change the color of the smoke from black to white?
Straight from the Wikipedia page about PAPAL CONCLAVE: Originally, damp straw was added to the fire to create dark smoke; beginning in 1963 coloring chemicals have been added, and beginning in 2005 bells ring after a successful election, to augment the white smoke, and especially if the white smoke is not unambiguously white.
Also from Wikipedia: Prior to 1945 (the year Pius XII changed the form of ballot to use anonymous oaths), when the ballots were of the more complex type illustrated above, the sealing wax which was used in those ballots had an effect in making the smoke from burning the ballots either black or white, depending on whether damp straw was added or not. This explains the confusion over the color of the smoke in the conclave of 1958, with coloring chemicals added beginning in 1963.