Who was Menelaus?
Menelaus was the son of Atreus, the brother of Agamemnon. Menelaus was the king of Sparta, because he had married Helen, the daughter of the old king of Sparta. He was married to Helen when Paris took Helen away to Troy, and it was Menelaus who insisted that his brother Agamemnon had to lead the Greek army to Troy to get Helen back - even at the cost of sacrificing Agamemnon's daughter (and Menelaus' niece) Iphigeneia.
Menelaus carrying Patroclos' body
(Roman copy, now in Florence)
After the Trojan War, Menelaus got Helen back and he sailed home with her. They didn't have any trouble getting home. They went right back to living in their house in Sparta and apparently got along fine. They appear in Homer's Odyssey.
Learn by doing:
More about the Trojan War
The Pride of Lions: The Story of the House of Atreus, by Norma Johnston (2002, unfortunately out of print right now, but maybe your library can find it). For teens.
The Iliad of Homer (Oxford Myths and Legends), by Barbara Leonie Picard. A retelling of the story.
Approaches to Teaching Homer's Iliad and Odyssey, by Kostas Myrsiades (1987).
The Iliad (Penguin Classics) by Homer. Translated by Robert Fagles.
The World of Odysseus, by Moses Finley and Bernard Knox (1954). A standard for anyone interested in Homer.