Removing the protective cellophane wrap should be done immediately upon arriving home with your flowers.
Note that quality flower sources will usually include a packet of fresh flower food.
Loosen the cellophane carefully - knives can easily pierce the flower food packet damaging it or flower stems.
Point the knives upward when cutting the cellophane.
An extra enclosure of packing can help protect the delicate flower heads better.
Remove everything, gently separating the flower heads that may be entangled during packing.
The flowers may seem mashed, but they will usually open naturally with a fresh under water cut and a long drink of water.