Tim,
Welcome to the world of the Crappy Camera. If you approach this as an adventure and with an open mind, you may (or may not, depending on your personal aesthetic) find that they make some pretty cool images. I assume you're joking about a 137 page manual. I can't imagine there being that much to explain...
If you get your Holga from Holgamods.com, you actually get two apertures (f8 and f11), along with a couple of other helpful mods. The website is cool to browse as well.
You're right, the build quality is not great. Light leaks are just one of the things that can go wrong (or right) with these cameras.
The freestyle link is good for a complete explanation of using the camera.
Michelle Bates has a good book on plastic cameras that I can recommend.
Good luck and have fun,
Steve
www.scdowellphoto.com