The Advent Wreath has four candles, 3 purple and one pink, each representing 1,000 years of waiting for Christ to appear. Each week starting on Sunday, another candle is lit, so that by the 4th week of Advent, all 4 candles are lit.
Purple is the liturgical color of the Advent season (the same as Lent), which represents penance.
The Third Sunday of Advent is called Gaudete Sunday. Gaudete (pronounced Gow-Day-Tay) means “rejoice” and on this day we celebrate that our waiting for Christmas is almost over. Rose is a liturgical color that is used to signify joy, so we light the rose candle on the third Sunday of Advent.
Although Advent wreaths come in different styles, the traditional circular wreath made of evergreens carries the added symbolization of eternal life in Christ.
Typically, families light the candles and say special prayers when they pray the blessing before dinner. There are many different prayer books that can be used with the Advent Wreath.
You can find some at this link: http://www.cptryon.org/prayer/adx/adwreath.html