Based on those parameters, Jubel then sends you two proposals with loose descriptions and activities (so as not to spoil the surprise). You pick one, then put down a deposit.
As Meredith Veit -- a journalist from Philadelphia who was one of Jubel's earlier clients -- put it after Jubel sent her to Indonesia, where she worked with orangutans and ate fresh lychees off the trees: "It was like I had planned my own perfectly orchestrated surprise."
You might spend your entire vacation in one place. You might also opt to visit a few different countries over a couple of weeks and not know what they are until you open your envelopes. Trips average less than a week, but you can go as long as you like. (And if you want to know specifically what you're doing, Jubel will spill.)