Please i need help with flash header

Hi to everyone, i have a big problem: i want to put a .swf file in my header (my theme is stardust) and i really don’t know where to start.
Can somebody give me very easy istructions, i’m not an expert.
Wich plug-in i need to install?
What i need to change?
I need help, i must be online for the end of the week.

Thank’s.

I saw tons of similar post, but no one with a good explenation.