The UI code starts from line (4), view [ ... ]. The view is a function that expects a window description as an argument. Note that this window description is just a code block using VID words. You could give it a name such as win, build this block with append or other code, and when you're ready, do view win. The view [] displays a minimal GUI window:
win: []; build up win with statements like append win [title "Currency rates"]view win
This allows for dynamically building screens based upon user input or events. There is also a built-in layout word in VID. Give your layout a name, and define it inside the block that follows, like this:
lay1: layout [a: area cyan 200x200]
layout builds a tree of face! objects from the ...