It’s nothing to be afraid of. Submissions usually include a CV so that the agent knows something about the author, a synopsis so that he knows something about the story, and sample writing so that he knows something of the author’s writing skills.
I believe that the CV and synopsis should only be one page each, and the sample exactly what the agent wants, usually around 50 pages.
It doesn’t matter how complex the story is, you need to summarise it on one page, and don’t keep any secrets from the agent, tell him what happens in your story, including the ending. Keep it simple.
Also, CV and synopsis – ordinary spacing, sample – double spacing.