Re: building foundationless honey supers
I am assuming you have a deep box on the bottom now for a brood box. I'm also assuming the super you want to add is not a deep box.
Here is what I've done in your situation:
When adding the super, I move a deep frame from the bottom box up into the super, near the middle. The deep frame hangs down into the deep bottom box from the upper super, with a space under it. The rest of the frames in the super were medium frames. The bees use that deep frame as a ladder into the added super, and draw out the foundationless frames fine. They also draw out comb off the bottom bar of that deep frame with the space under it. After the super has started being drawn well, I remove the deep frame, cut off the comb under it, and put it back in place in the bottom box. I then tie in the drawn comb I cut off that deep frame into another super frame, and put it in place in the space now created for it in the super.
As they start drawing the foundation frames in the super, I keep watch and rotate the frames towards center where they've started drawing, to help keep the combs drawing out straight. As they get a comb drawn or mostly so, I'll rotate a frame in from the outside edges in a checkerboard fashion, it helps to get nice straight combs in the super. I do this for cut comb honey, it has worked very well for me.
Best of luck!
20+ years, raise my own queens, feed when needed, I treat but have not perfected varroa management yet.