Hello and Welcome!
If you are talking about after the priest says:
The peace of the Lord be with you always and the congregation replies:
***And also with you.
***Then the deacon or priest may add: **Let us offer each other the sign of peace.
**Then we pray together the Agnus Dei or Lamb of God.
**Agnus Dei, qui tollis peccata mundi: (pronounced an-yoos day-ee)
miserere nobis.
Agnus Dei, qui tollis peccate mundi:
miserere nobis.
Agnus Dei, qui tollis peccata mundi:
dona nobis pacem.
or in English:
Lamb of God, you take away the sins of the world:
have mercy on us.
Lamb of God, you take away the sins of the world:
have mercy on us.
Lamb of God, you take away the sins of the world:
grant us peace.
**I suggest you find yourself a Missal or subscribe to
Magnificat where you will find the order of the Mass and readings for each Mass. It will help you so much!
God bless you,
Kelly