Remember, you can check the full document Paschale Solemnitatis on this site, among many on the internet.
If Passion Sunday is notable for what people “get,” namely a green branch, the liturgical highlight is the procession after the proclamation of the Gospel.
29. The commemoration of the entrance of the Lord into Jerusalem has, according to ancient custom, been celebrated with a solemn procession, in which the faithful in song and gesture imitate the Hebrew children who went to meet the Lord singing “Hosanna”. (Cf. Roman Missal, Passion Sunday (Palm Sunday) n. 9)
Some believers–and I might count myself among them–are uneasy about playacting an event. That it reflects Christ’s triumph over death and/or at the end of time does make it go down easier. But we should realize that many times during Holy Week, we get a “wink,” as it were: a reminder that betrayal, persecution, suffering, and death are not the end. If only we were able to take our approach to sin in this way: acknowledge the reality, but rely more heavily on God’s grace.
By the book, a parish gets to do one big procession, in which people gather in a place other than the main worship space:
The procession may take place only once, before the Mass which has the largest attendance, even if this should be in the evening either of Saturday or Sunday. The congregation should assemble in a secondary church or chapel or in some other suitable place distinct from the church to which the procession will move.
How the procession aligns:
In this procession the faithful carry palm or other branches. The priest and the ministers, also carrying branches, precede the people. (Cf. Ceremonial of Bishops, 270)
A brief reminder about the palm “or other” branches.
The palms or branches are blessed so that they can be carried in the procession. The palms should be taken home, where they will serve as a reminder of the victory of Christ which they celebrated in the procession.
How often do First Worlders use “other” branches?
Pastors should make every effort to ensure that this procession in honor of Christ the King be so prepared and celebrated that it is of great spiritual significance in the life of the faithful.
What sort of preparations have you experienced that have helped this aspect? Or is the procession something of a must-do imposed on one of the worshiping communities of a parish? How might we move beyond that? Is it more than getting children excited?