Nowadays you kids have websites and videos, but back in the olden days the ancient ways were handed on via email. From the archives of a mailing list I was on back in the ’90s:
“As far as I can tell, the palm should be “fresh,” meaning that you probably should do this when you get home from church on Palm Sunday. Pat and I debated whether crosses could be made with palms a few days old (and drying) and soaked in water to limber them up. Anyway …
Split the palm lengthway. Typically the palm is “hinged.” Split it at the hinge. You should have two long slender palms. Take one.
About one fifth up from the broad end (the bottom), fold down. Take the longer of the halves and fold up and to the right about a third from the first fold (now the top). With this second fold, you are forming part of the crossbeam.
You are now going to make the third fold, and thus the length of the crossbeam to the right. Find a point on the palm facing away from the cross (from that second fold) that is about the same distance from the center of the cross as is the top part of it. Fold to bring the palm back toward the cross and forming the crossbeam.
For the fourth fold, again, find a point on the left half of the crossbeam equal in distance from the center of the cross as the right side. Fold to bring the palm back to the body of the cross, completing the crossbeam. The cross itself is finished, but it won’t hold without completing the finishing work.
Take the remaining palm and fold up and to the right, folding over that corner. What you are going to do is wrap the remaining palm around from the top corner, over the front and to the bottom opposite corner. Bring it up the back, to the upper right corner again and repeat. As you bring the remaining palm back around, bring it horizontally across the back. As you bring the palm back toward the front again, bring it across the front to the opposite corner and around to the back. The front should almost like draped cloths criss-crossing the cross.
Should should have a couple inches of very thining palm remaining. Take the remaining palm and thread it in and around the layers in the back (much like taking thread and weaving it in and out of itself when sewing, to finish it off.). Flatten it out, take any kiltering out of the cross and you should have the finished product.
I hope these instructions made sense. I’m a communicator by trade, but I am very accustomed to having visual aids present!