Short answers, pulled from the story.
Theseus had two claimed fathers: Aegeus, king of Athens, and the god Poseidon, both of whom were said to have fathered him on the same night with his mother Aethra, princess of Troezen. This dual paternity gave him both mortal and divine characteristics, a common feature of Greek heroes.
Ariadne, daughter of King Minos, gave Theseus a ball of thread on the advice of Daedalus, which he tied to the doorpost before entering. Following instructions to always go forward and always go down, he reached the Minotaur at the heart of the maze, overpowered it, and stabbed it in the throat with a sword he had concealed inside his tunic.
The Athenians preserved the thirty-oared galley Theseus sailed to Crete by replacing each plank as it rotted, over many centuries. Philosophers noted that if every original plank was eventually replaced, it was unclear whether the resulting vessel was still the same ship, raising questions about identity and continuity that remain a standard example in philosophy.
On the overland route from Troezen to Athens, Theseus defeated six bandits: Periphetes the Club Bearer at Epidaurus, Sinis the Pine-Bender at the Isthmus, the Crommyonian Sow near Crommyon, Sciron near Megara, Cercyon at Eleusis, and Procrustes the Stretcher on the plain of Eleusis. In each case he killed the enemy using their own method.
Aegeus died by throwing himself off the cliffs of Sounion into the sea. He had agreed with Theseus that a white sail would signal a safe return from Crete; Theseus forgot to change the black sail, and Aegeus, believing his son was dead, leaped to his death. The body of water was named the Aegean Sea after him.
In 475 BC, the Athenian general Cimon conquered the island of Skyros following an oracle and identified remains he believed to be those of Theseus: a coffin containing a large skeleton with a bronze spear-head and a sword. The remains were reburied in Athens.