In a word, the Rosary presents the life of Christ, as seen through his Mother’s eyes.
The Joyful Mysteries present the early life of Christ, from the Annunciation through the Finding in the Temple. The Luminous Mysteries present his public ministry, from his Baptism in the River Jordan through the institution of the Eucharist. The Sorrowful Mysteries recall his Passion — from his Agony in the Garden to his Crucifixion. And the Glorious Mysteries recount his Resurrection, Ascension into Heaven, followed by the descent of the Holy Spirit and the Assumption of His Mother and her crowning as Queen of Heaven and Earth.
An excellent instruction on how to pray the Rosary can be found here.
If you are new to saying the Rosary, these online versions may help. For those experienced in saying the Rosary, they may provide welcome variations:
The Rosary online, from the Cathedral of Mary Our Queen, Baltimore
You can buy Rosaries from a number of sources, including our Shop.