Hello jmcrea.
I have read John 20:22 and have a few questions.
- How does Jesus’ instructions to his follows transpire 2000 years later?
The Pope and the Bishops are the lawful successors of those to whom Jesus gave this instruction. Under the power of the Keys, given to St. Peter and his successors (Bishop of Rome) in Matthew 16:18-19, the form of the Sacrament is subject to the discipline of the Church. Over time, the Sacrament has taken a couple of different forms - first of all, public Confession at the beginning of Mass, followed by public Absolution given by the presiding Bishop. (Vestiges of this remain in the Mass in the form of the Penitential Rite.) Then in the 200s AD we find that penitents are going privately to priest-Confessors to receive advice about which sins they need to confess publicly at Mass. In Ireland in the 600s AD, missionary priests found that the people were too shy to confess their sins at Mass, and were in danger of neglecting the Sacrament of Penance altogether, so they dispensed with the public aspect of it, keeping it private between priest and penitent only.
This model spread throughout the whole world and became the official norm for Confession about a hundred years later. (The Church is like a nomadic tribe that travels at the pace of its slowest member - things do not change very quickly around here.)
This is still the norm today.
2)Were his intructions not to his followers and his followers only?
You will no doubt recall that the disciples were hiding in the Upper Room behind locked doors so as not to be discovered by the Jewish authorities, and that Jesus had come to them by passing through the locked door, to greet them and to give them this instruction, after having died as the Sacrifice for sins, and having that same morning risen from the dead.
- How were sins forgiven prior to John 20:22?
By means of public confession of sins to the Levites (Hebrew Jewish priests), together with the offering of the appropriate animal for that sin, which would then be “burned” (cooked) and eaten by the priest and penitent in a sacrificial meal together, with the burned-up parts being assumed to be being eaten by God and His Angels invisibly in union with the penitent(s) and priest(s) present at the Sacrifice. The killing of the animal was what took away the sin, and the eating of its flesh in the communal meal with God’s priest was what brought the penitent back into union with God through His priest.