THE ADVENT SEASON

The First Sunday of Advent marks the beginning of the new liturgical year. Advent is a season of great anticipation of the coming of Christ, focusing on both Jesus’ coming in history and his final coming as the Lord and judge. During Advent, we prepare our hearts to celebrate the Nativity of our Lord (Christmas).
An Advent Prayer
We long for your coming, Lord Jesus. Our hearts are empty until you fill them with your presence. As we prepare to celebrate the feast of your historical coming, fill us with your Spirit so that we may be prepared for your Second Coming, when we will enjoy your presence forever. Amen

The Advent Wreath
The Advent Wreath helps us mark the four weeks of preparation for Christmas. Advent wreaths traditionally consist of a circle of evergreen branches with four candles, three purple and one pink or rose colored. The purple candles symbolize the prayer, penance and preparation that mark the Advent season. The rose-colored or pink candle coincides with the Third Sunday of Advent, Gaudete Sunday. The Third Sunday of Advent, on which the priest may wear rose, is a time of celebration, noting that Advent is nearing completion and Christmas is near.
During Advent, candles are progressively lit week by week, beginning with a single purple candle. During the second week, two purple candles are lit, followed by two purple candles and the pink candle during the third week, and then all four candles.
The blessing of an Advent Wreath traditionally takes place on the First Sunday of Advent or on the evening before the First Sunday of Advent. When the blessing of the Advent Wreath is celebrated in the home, it is appropriate that it be blessed by a parent or another member of the family. Then, on each day in Advent, perhaps at a family meal, the candles are lighted: one candle the first week, two the second, and so forth. Prayers for each week can be found at https://www.loyolapress.com/our-catholic-faith/liturgical-year/advent/prayers/prayer-for-lighting-the-advent-wreath-candles
The blessing below is from "Catholic Household Blessings and Prayers," as used on the USCCB website.
 

THE BLESSING OF AN ADVENT WREATH

All make the sign of the cross as the Leader says: Our help is in the name of the Lord.

Response:  Who made heaven and earth.
Then  Isaiah 9: (lines 1-2 and 5-6) or Isaiah 63 (lines 16-17 & 19)
or Isaiah 64  (lines 2-7) is read:
Reader: The Word of the Lord.
Response: Thanks be to God.

With hands joined, the leader says:
Lord our God,
we praise you for your Son, Jesus Christ: he is Emmanuel, the hope of the peoples,
he is the wisdom that teaches and guides us, he is the Savior of every nation.

Lord God,
let your blessing come upon us as we light the candles of this wreath.

May the wreath and its light be a sign
of Christ’s promise to bring us salvation.

May he come quickly and not delay.
We ask this through Christ our Lord.
Response: Amen.

The blessing may conclude with a verse from
“O Come, O Come, Emmanuel”:
O come, desire of nations, bind
in one the hearts of humankind;
bid ev’ry sad division cease
and be thyself our Prince of peace.
Rejoice! Rejoice! Emmanuel
shall come to thee, O Israel.

—From “Catholic Household Blessings & Prayers”: