In Panorama, “append” means to add records on to the bottom, there’s no key involved. You are using “append” to mean appending new field on the right, basically similar to an SQL join operation. It might someday, but Panorama doesn’t currently have an integrated operation like that. The only way to do it is with the technique John described. If I was doing this myself, I would add field “B” manually, but the rest of the steps I would do in procedure code, like this:
The advantage of using procedure code is simply that I can easily edit the code and run it over again and again if needed, for example if I made a mistake. If you use the Morph Field command you would have to type the formula in again each time.