just mount it on your camera and start shooting...
set it to ttl or ttl bl to start...
inside you want to point the flash head toward the ceiling to bounce the light instead of blasting someone away......
later on there are many things you can do with an sb800.... experiment with it off camera... play with the bounce card.... play with the gels etc...
the sb800 manual also includes a how to use guide.. read that for some ideas..
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