A medium on top and wait for them to move up can work. If you're impatient you can speed things along a bit. Pull out any empty frames in the deep and put medium frames in the middle of the brood (alternate with brood). When you have some brood in some of the mediums, move them up to the medium box above an excluder along with the queen and put some more mediums in the deep in their place. When the brood in the deep have emerged, harvest the box, cut any extra comb off the bottom of the mediums and move them up to the upper box as well.