…Does the church have any guidance on the introduction?..
I am not aware of any encouragement to have announcements before the Entrance Hymn. The emphasis is on prayer and silence. So if they were considered necessary, I would encourage them to be short and to the point.
The GIRM refers to an introduction to the Mass. But it is
after the hymn, the procession, the Sign of the Cross and the greeting.
From the 2002 General Instruction of the Roman Missal (GIRM) approved for the USA, which can be accessed from
romanrite.com/girm.html :
“50. … After the greeting of the people, the priest, the deacon, or a lay minister may very briefly introduce the faithful to the Mass of the day.”
“105. The following also exercise a liturgical function:
b. The commentator, who provides the faithful, when appropriate, with brief explanations and commentaries with the purpose of introducing them to the celebration and preparing them to understand it better. The commentator’s remarks must be meticulously prepared and clear though brief. In performing this function the commentator stands in an appropriate place facing the faithful, but not at the ambo. …
d. Those who, in some places, meet the faithful at the church entrance, lead them to
appropriate places, and direct processions.”
Near the back of the Roman Missal there are prayers under the heading “PREPARATION FOR MASS”, in Latin “PRAEPARATIO AD MISSAM” (Missale Romanum, Libreria Editrice Vaticana, 2002, ISBN: 8820972719, page 1289). These are the Prayer of St. Ambrose, Prayer of St. Thomas Aquinas, Prayer to the Blessed Virgin Mary and one called “Formula intentionis”. The last one is intended for priests, beginning: “My purpose is to celebrate Mass and to make present the body and blood of our Lord Jesus Christ …” (Daily Roman Missal, Scepter Publishers, Princeton, New Jersey, 1996, ISBN 0933932588, page 1961).
Silence is encouraged before the Mass, from the GIRM: “45. … Even before the celebration itself, it is commendable that silence to be observed in the church, in the sacristy, in the vesting room, and in adjacent areas, so that all may dispose themselves to carry out the sacred action in a devout and fitting manner.”
A particular time in the Mass is given for announcements, from the GIRM: “166. When the prayer after Communion is concluded, brief announcements to the people may be made, if they are needed.”