Q.transplanting camellias
I have to transplant about 12 8-year-old camellia flowering plants to large pots. They are about five/six feet tall. What is the best way of doing it without damaging the plants?

These articles will help you with transplanting itself:
https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm
https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm
When I have to repot a plant that large, I find it easiest to do by laying them down. This makes it easier to handle them and they are less likely to be damaged by falling over. A long knife should be run around the inside of the pot to loosen the roots from the pot.