To get started, you click the "Browse..." button at the bottom and browse to wherever you installed the game exe, then click "Run and Record New Movie" (or "Run and Play Existing Movie" if you already started recording it). After that it's standard re-recording emulator controls from there (for example, you can press backslash to frame advance), and you can see and configure those controls by choosing "Input > Configure Hotkeys..." from the menu. Maybe I'll make a proper instructions page at some point, but it should all be pretty familiar to someone who's used re-recording emulators before, and the Hourglass-specific problems to watch out for are hopefully only temporary.
But... this particular game doesn't work at all in Hourglass yet, so you might want to try some game that's known to work instead, and if you can it's best to use a computer that has Windows XP, for now.