New flash user - A few question please

Hello everyone,
Recently I got my new flash, a used 550EX.
This is my first flash and I have no idea how to use it. I'm learning from the tutorials on the web and from this great forum!

So, to the questions:

1. How can I shot in dark places with flash and high speed?
I tried to shot at night with ETTL and tilted up flash. The shutter speed was 1sec!!! 1 sec is way too much for taking pictures at night. ( iso400 ) How can I speed up the shot? ( only by flash functions)

2. When I press both "+" and "-" on the flash unit, I got "H" flash. When do I need to use it? The second press on both buttons get me " 2 flash mode", at the beggining and at the end of the singe shot. What is it for?

3. Multi mode. What is it for? Isn't it like a Manual mode?

4. White card. As you know, 550ex doesn't have a white card. Can I make one from a white paper? What is the recomended on flash defuser for outdoor photography?

Thanks a lot,
Vovka.

1. Use manual mode and set the shutter speed yourself.
2. H means high speed sync. I believe "2 flash mode" is second curtain sync, where the flash happens at the end of the exposure. The first flash is the pre-flash.
3. It's for multiple flashes in the same exposure. Special effects.
4. Index card and rubber band will do fine.

Flash Photography 101, and the other links in my sig, will help you a lot.

I'll expand a little bit on Curtis N's point with #1. If the flash it in ETTL mode and the camera is in Av (or Tv) mode, the camera will try to make an exposure based on the available light without the flash, then fires the flash only as a "fill flash" to lighten up the shadows a little. In P mode in the dark, the camera will set itself at what it thinks are the right settings for flash, usually 1/60 at f/4, and on ETTL, the flash will produce what the camera thinks is the right amount of light for the picture. In M mode, you set the shutter speed and aperture you want to use and on ETTL, the flash will produce what the camera thinks is the right amount of light for the picture. Just remember that, unless you have set the flash for high speed sync (H), you will have to keep the shutter speed below the flash sync speed for your camera - usually 1/200 or 1/250.

Also, I can't tell if you are tilting your flash up outdoors or indoors. I hope it is indoors, but if it is outdoors, you are only sending light off into space.

For item #4, I wouldn't use a diffuser outdoors unless it is a really big one. If it is too small, you won't see the effect of it, but you will lose light.