How do the deceased reach Hades?
The deceased reach the Underworld by Charon the ferryman. If he is paid his fee he will take souls across the river. Thus the custom of placing coins over the eyes of a corpse. So the soul can afford to pay Charon.
Everyone goes to the underworld in Greek, everyone. Answer 2 Yes, but Sisyphus went to the part of Hades, called Tartarus, where bad people were punished. He was sly and evil and used to way-lay travelers and murder them. He betrayed the secrets of the gods and chained the god of death, Thanatos, so the deceased could not reach the underworld. Hades himself intervened and Sisyphus was severely punished
After Zeus has the five sacred items, Hercules will help you reach the throne rooms of Poseidon and Hades, where you get the Trident and the Hades Crown. Return to the gate, and Hercules will smash open the padlock. To reach the top, you will need the one-drachma coin from cleaning graffiti at the Temple of Hades. (see related question)
At the Temple of Hades, enter Hades' realm by using the pomegranates from the tree in the Garden of the Sphinx. To open the Throne Room, you will need Hercules. After you collect all of the mythical stuff Zeus tells you to get, Zeus steals them from you, and Hercules will finally help you to reach both Hades' and Poseidon's lairs. *You will need the Touchscreen Mirror from the test by Aphrodite on the beach.
Once you have recovered the 5 sacred items and Zeus takes them, you can get Hercules to help you at last. He will kick away the large rock to reach Poseidon, and also move the boulder to let you reach Hades. Once you have the Trident and the Hades Crown, Hercules will also smash the padlock on the Olympus gate.
You get the Crown from Hades after Zeus takes the sacred items. Together with the Trident from Poseidon, it lets you battle Zeus on Mount Olympus. After Zeus takes the sacred items, Hercules will help you reach the throne rooms of Hades and Poseidon. You will need the Touchscreen Mirror from Aphrodite's test on the beach in Poseidon's realm.