The Ceremonial of Bishops gives a detailed description of how to make the sign of the cross at n. 108 and footnote 81.
First it has in n. 108: “When the bishop signs himself with the sign of the cross or when he gives a blessing,[footnote 81] he places his left hand on his breast, unless he is holding something.”
In footnote 81:" “When making the sign of the cross, he holds the palm of the right hand hand turned toward himself, with all the fingers joined and held straight, and makes the sign of the cross by moving this hand from head to chest and from left shoulder to right. …” (Missale Romanum, ed. 1962, Ritus servandus in celebratione Missae, III, 5)."
From Ceremonial of Bishops, Liturgical Press, 1989, ISBN 0-8146-1818-9, page 44. This is a translation of Caermoniale Episcoporum, Libreria Editrice Vaticanan, 1984 (reprinted 1995), ISBN 88-209-4217-8, page 36. It is an official liturgical book.
The words in making the sign of the cross at the beginning of Mass are “In the name of the Father, and of the Son, and of the Holy Spirit.” The people respond “Amen”. In Latin the words are: “In nomine Patris, et Filii, et Spiritus Sancti.”
This is the standard sign of the cross. Other “signs of the cross” are the signing on the forehead, lips and breast before the gospel. Another is when a priest blesses something.