Sacraments are outward signs, instituted by Jesus, to give us grace. There are seven sacraments: Baptism, Confirmation, Eucharist, Penance, Anointing of the Sick, Holy Orders, and Matrimony. The outward elements of sacraments, such as the water and words used in Baptism, are perceptible to our senses and help us understand the reality of the inner, invisible grace we are receiving. Grace is an unmeritied gift of God and the Sacraments were established by Christ and entrusted to the Church to give us access to this share in God's own life.
To learn more about Liturgy and Sacraments, please see the following resources:
Catholic Sacraments, Vehicles of Grace
The Seven Sacraments, Catechism of the Catholic Church
Celebrating the Church's Liturgy, Catechism of the Catholic Church
Sacraments, Channels of Divine Grace, Father Hardon
These Are The Sacraments, Archbishop Fulton J. Sheen
They are the divine helps which God gives us to enable us to:
Baptism
Eucharist
Reconciliation
Confirmation
Marriage
Anointing of the Sick
Holy Orders