When you are switching boxes, it gets a bit tricky. You need two flat roof and inner cover setups, for example one each side of the hive. You empty the upper brood box into a spare box on one side. Now you need to either be able to lift the lower box, or move each frame into another box on the other side. Then you can put an empty box back onto the bottom board, and refill it from the first box you emptied. Then repeat from the other side with the second box.
My problem is that my apiary space is tiny - around 2 x 2 meters for 2 hives. I don’t have space to put extra boxes on both sides of the hives, plus have space for working. So unless I can lift, I can’t switch in the manner discussed. As I can’t lift a whole box, I just rotate frames out or split for swarm control.