Note, I'm not a theologian. I tried to figue this out, and I think I have it right, but I might not. This is copied from a Church in Ireland.
1. Plenary Indulgence of 2 November
From 12 noon on 1 November until midnight on 2 November one plenary indulgence (applicable only to the Holy Souls) may be gained by visiting a church or oratory and recite the Our Father and the Creed there.
Conditions for gaining a plenary indulgence:
Go to Confession (in the week preceding or the week following 1 November)
Receive Holy Communion (1 Holy Communion for each indulgence)
Pray for the Pope’s intentions (one Our Father, and Hail Mary or any other prayer of one’s choice)
One should have the desire to be detached from every attraction to sin, even the slightest
2. 1 — 8 November
The faithful who visit a cemetery and pray for the dead, may gain a plenary indulgence (applicable only to the Holy Souls) once per day from 1 to 8 November.
The above conditions regarding Confession, Holy Communion and prayer for the Pope’s intentions apply also for this.
3. What is an Indulgence?
“An indulgence is a remission before God of the temporal punishment due to sins whose guilt has already been forgiven, which the faithful Christian who is duly disposed gains under certain prescribed conditions through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints” (Paul VI, Apostolic Constitution, Indulgentiarum doctrina, Norm 1).
“An indulgence is partial or plenary according as it removes either part or all of the temporal punishment due to sin” (Indulgentiarum doctrina, Norm 2; Cf. Norm 3). The faithful can gain Indulgences for themselves or apply them to the dead (Code of Canon Law, can. 994).
From Catechism of the Catholic Church, no 1471
