You've got a whole book of answers in those questions, so I am going to start by telling you to do a BYC search. There are threads, forums, videos, etc. all dedicated to those topics.
However:
To candle an egg, you need a dark room and a flashlight. And an egg. Position the flashlight so the light shines through the egg. With light-colored eggs, you will be able to see development of the chicks by day 5. There are tons of pictures on BYC to show you developing and dead eggs.
Sexing chicks is very, very difficult unless you are hatching a sex-linked breed. Sex-linked chickens hatch with boys being one color, girls another. If the breed is not a sex-linked breed, you'll have to wait until the chicks have grown out to determine gender.