The General Instruction of the Roman Missal has:
“150. A little before the Consecration, if appropriate, a minister rings a small bell as a sign to the faithful. The minister also rings the small bell at each elevation by the Priest, according to local custom.”
For the Thursday of the Lord’s Supper, the Roman Missal has:
“7. The Gloria in excelsis Deo (Glory to God in the highest), is said. While the hymn is being sung, bells are rung, and when it is finished, they remain silence until the Gloria in excelsis of the Easter Vigil, unless, if appropriate, the Diocesan Bishop has decided otherwise.”
For the Easter Vigil, the Roman Missal has:
“31. After the last reading from the Old Testament with its Responsorial Psalm and its prayer, the altar candles are lit, and the Priest intones the hymn Gloria in excelsis Deo (Glory to God in the highest), which is taken up by all, while bells are rung, according to local custom.”
[Excerpts from the English translation of The Roman Missal © 2010, International Commission on English in the Liturgy Corporation. All rights reserved.]