Missing Materials:
Did you download the presets? If you have nothing in your material library, you need to DL that. It is free. Just close Bryce, copy the files in place (or use the installer if there is one).
Once you get Bryce so it works, begin by just poking it a bit. Hikaro's tutorial is a good place to begin. It won't get you all the way, but it should give you enough insight so you can figure out what questions to ask next.
Bryce is the simplest, easiest 3d program you will ever use. But, it will not feel like this until you have played around with it for a few weeks.
so recap:
step 1: get the rest of Bryce 5.5
step 2: follow Hikaro's tutorial step by step. If it doesn't make sense, you can always ask.
Don't worry, you can get all the help you need. You can get the same blank scene (with the cameras already set, etc) that we all use.