Elena 
The plenary indulgences listed below are associated with Triduum:
1) Grant #7.1.2- Eucharistic Adoration and Procession – Holy Thursday
Plenary indulgence
The faithful who piously recite the Tantum Ergo after the Mass of the Lord’s Supper on Holy Thursday during the solemn reposition of the Most Blessed Sacrament may receive a plenary indulgence.
A partial indulgence is granted for visiting the Blessed Sacrament for adoration or for offering any approved prayer to Jesus present in the Blessed Sacrament.
2) Grant #13 – Memory of Passion and Death – Good Friday
Plenary indulgence
A plenary indulgence may be won by the faithful who, on Good Friday, participate in the Adoration of the Cross during solemn liturgy.
3) Grant #28 – Renewal of Baptismal Vows – Holy Saturday
Plenary Indulgence
A plenary indulgence is granted to the faithful who at the celebration of the Easter Vigil or on the anniversary of their own Baptism, renew their baptismal vows in any legitimately approved formula.
Tantum Ergo – Holy Thursday
Tantum ergo Sacramentum
Veneremur cernui:
Et antiquum documentum
Novo cedat ritui:
Praestet fides supplementum
Sensuum defectui.
Genitori, Genitoque
Laus et iubilatio,
Salus, honor, virtus quoque
Sit et benedictio:
Procedenti ab utroque
Compar sit laudatio.
Amen.
V. Panem de caelo praestitisti eis.
R. Omne delectamentum in se habentem.
Oremus: Deus, qui nobis sub sacramento mirabili, passionis tuae memoriam reliquisti: tribue, quaesumus, ita nos corporis et sanguinis tui sacra mysteria venerari, ut redemptionis tuae fructum in nobis iugiter sentiamus. Qui vivis et regnas in saecula saeculorum.
R. Amen.
English Translation
Down in adoration falling,
Lo! the sacred Host we hail,
Lo! oe’r ancient forms departing
Newer rites of grace prevail;
Faith for all defects supplying,
Where the feeble senses fail.
To the everlasting Father,
And the Son Who reigns on high
With the Holy Spirit proceeding
Forth from each eternally,
Be salvation, honor, blessing,
Might and endless majesty.
Amen.
R. Thou hast given them bread from heaven.
V. Having within it all sweetness.
Let us pray: O God, who in this wonderful Sacrament left us a memorial of Thy Passion: grant, we implore Thee, that we may so venerate the sacred mysteries of Thy Body and Blood, as always to be conscious of the fruit of Thy Redemption. Thou who livest and reignest forever and ever.
R. Amen.
Renewal of Baptismal Vows – Holy Saturday
V. Do you reject Satan?
R. I do.
V. And all his works?
R. I do.
V. And all his empty promises?
R. I do.
V. Do you believe in God, the Father Almighty, creator of heaven and earth?
R. I do.
V. Do you believe in Jesus Christ, his only Son, our Lord, who was born of the Virgin Mary was crucified, died, and was buried, rose from the dead, and is now seated at the right hand of the Father?
R. I do.
V. Do you believe in the Holy Spirit, the holy Catholic church, the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting?
R. I do.
V. God, the all-powerful Father of our Lord Jesus Christ has given us a new birth by water and the Holy Spirit, and forgiven all our sins. May he also keep us faithful to our Lord Jesus Christ for ever and ever.
Requirements for obtaining a plenary indulgence:
Do the work while in a state of grace,
Receive Sacramental confession within 20 days of the work (several plenary indulgences may be earned per reception),
Receive Eucharistic communion (one plenary indulgence may be earned per reception),
Pray for the pope’s intentions (Our Father and Hail Mary, or other appropriate prayer, is sufficient),
Have no attachment to sin (even venial) – i.e., it is sufficient that the Christian makes an act of the will to love God and despise sin.
Requirements for a partial indulgence:The work must be done while in a state of grace and with the general intention of earning an indulgence.
Notes:
Only baptized persons in a state of grace who generally intend to do so may earn indulgences.
Indulgences cannot be applied to the living, but only to the one doing the work or to the dead.
Only one plenary indulgence per day can be earned (except for prayer at the hour of one’s own death).
Several partial indulgences can be earned during the same day.
If only part of a work with plenary indulgence attached is completed, a partial indulgence still obtains.
If the penance assigned in confession has indulgences attached, the one work can satisfy both penance and indulgence.
Confessors may commute the work or the conditions if the penitent cannot perform them due to legitimate obstacles.
In groups, indulgenced prayer must be recited by at least one member while the others at least mentally follow the prayer.
If speech/hearing impairments make recitation impossible, mental expression or reading of the prayer is sufficient.
For an indulgence attached to a particular day requiring a church visit, the day begins at noon the day before and ends at midnight.