I thought you might like to better understand what’s happening at Sunday mass There are two main parts, the Liturgy of the Word and Liturgy of the Eucharist. "Liturgy" comes from the Greek word meaning "public worship," and "Eucharist” from "thanksgiving."
First the introductory rites. The priest and his party process to the altar while the people sing. After a greeting, during the Easter season the priest sprinkles the people as a reminder of baptism; this also happens occasionally at other times of the year. (If the sprinkling takes place, there is no penitential act, that being when we confess, or beg “Lord, have mercy.”) Then comes the Gloria, followed by the Collect, or opening prayer.
Now the Liturgy of the Word begins. The first reading is usually from the Old Testament and is almost always related to the theme of the Gospel reading. The psalm is also related to the Gospel reading, but the second reading is not. It usually comes from one of the letters of St. Paul. Now comes the homily, based on the readings which preceded it. After the homily, all join in the profession of faith.
An interlude follows, during which the priest prepares the altar, the people sing, and the collection is made and brought to the altar. In our parish people bring food and this is also placed on the altar. The theology is that all these represent the gifts of the people to the church, not only the money but everything the people give, including the time and talent they offer to the parish and the wider church.
Now the Liturgy of the Eucharist begins with a short dialog between priest and assembly (“the Lord be with you”). The Eucharistic prayer proper starts with a short preface followed by a sung acclamation by the people. In the next part of the prayer the priest hold up the bread and wine, and by his words they are transformed into the Body and Blood of Christ. The people proclaim the mystery of faith (Christ died, was resurrected, and will come again). The prayer continues with the offering of the Body and Blood to the Father* with a plea that by partaking of the Body and Blood we may be gathered together as one in the Holy Spirit, and that the church and its members may be blessed and unified. The Eucharistic prayer ends with a doxology an invocation of the three Persons of the Trinity).
Then the people pray the Lord’s prayer and offer one another the sign of peace. After the Lamb of God, they join in the communion procession, during which the people sing. There is a period of silence, and then then the prayer after communion. The people are then sent forth with a blessing by the priest.
* A fairly complex theology stands behind this act. We believe that there is only one God. But there are three Persons (the Trinity) who embody God. One, yet three. A mystery. During the Eucharist, things of this world (the bread and wine, made by human hands) become the Body and Blood of Christ. Ordinary things become holy, and not just any kind of holy, but the body and blood shed by Jesus on the cross, which represent the saving sacrifice he made for us. In a sense, this was when the human Jesus became the divine Christ. Our concept of Jesus/Christ is that he is both human and divine, another mystery.
When the priest offers the Body and Blood to the Father, he is actually offering Christ. But this is the Christ who has come among us through the consecration of the Body and Blood.