What exactly did Giuseppe Garibaldi do to unite Italy?

he led an army of 1,000 soldiers know as Red Shirts on a campaign trough Southern Italy against the Kingdom of the Two Siclies which was Sicily and Southern Italy. They captured Sicily then crossed the Strait of Messina onto mainland Italy. They captured the capital of Naples then besieged King Francis II of the Two Sicilies, his wife and their men at the Siege of Gaeta in 1860-61 when they surrendered to Garibaldi and his men. After that he turned this territory over to the Kingdom of Sardinia which had unified most of Northern and Central Italy to form the Kingdom of Italy.