What is this part of the Mass?
The Liturgy of the Eucharist begins with the Presentation and Preparation of the Gifts. The priest prepares the altar for sacrifice while the gifts of bread and wine are brought forward by lay members of the assembly.
 
What do we say now and what is changing?
There are very few changes to this part of the Mass as you will see. They occur when the priest extends his hands and invites us to pray over the sacrifice of bread and wine:

Priest: Pray, brethren, that my sacrifice and yours may be acceptable to God, the almighty Father
People: (please respond together) May the Lord accept this sacrifice at your hands for the praise and glory of his name, for our good and the good of all his holy Church.

The Church is indeed holy – it is one of the four marks of the true Church: “one, holy, catholic, and apostolic.” It does not mean that every individual in the Church is holy in conduct – we must always remember that Judas was one of the Twelve. What is does mean is that the indwelling Spirit of God – the Spirit of holiness – makes holiness possible for all who freely cooperate with God’s grace.

The Eucharistic Prayer follows, which is the center and summit of the Holy Mass. Together with the priest we all join ourselves with Christ to proclaim the marvelous and wonderful deeds of God. At the beginning of the Eucharistic Prayer, we exchange a dialogue with the priest in the Preface (PREF-iss) Dialogue, the Sanctus (SONK-toos), and the Memorial Acclamation, and conclude with the great Amen. During most of the Eucharistic Prayer however, we listen and pray in silence along with the priest.

There is more than one Eucharistic Prayer. All have been affected to some extent by the new translation. Eucharistic Prayer 1 predates Vatican II and is for use on Sundays, Saint’s feast days, and at Christmas, Holy Thursday, and Easter. Eucharistic Prayer 2 is the shortest and is based on a prayer dating back to the 3^rd century. It is for use in weekday Masses. Eucharistic Prayer 3 was written after Vatican II and is used on Sundays and feast days. Eucharistic Prayer 4 is based on a 4^th century prayer from the Eastern Tradition of the Church. It is intended to be used during Ordinary Time only. The changes you will hear will better reflect the words and phrasing of the Latin.

The preface dialogue begins with the liturgical exchange we’ve already looked at.  All together now: “The Lord be with you / And with your spirit.” Then, the priest will invite us to “Let us give thanks to the Lord, our God,” and you will respond (raise hands here): “It is right and just.” This is a more concise translation of the Latin, and it creates an almost seamless transition into the rest of the Eucharistic Prayer. For us not to give thanks (“Eucharistia”) to God for his great gifts and graces to us – supremely for the gift of his Son – would indeed be a grave injustice.