I did pick destination boxes from the drop down each time, and I entered the number of days each time.

As a side question, what happens if I want to start in one place, and finish somewhere else? Suppose, for example, I want Paris -> Atlanta -> Sydney -> London : is that possible?

If this works properly and well I can see that I would not only use it, but would pay money for it, but at the moment, for me, it doesn't seem to be working.

FWIW, I'm well-known in my companies for breaking anything that people think is ready to go and suitable for deployment to muggles, so these teething problems are to be expected.