Getting started with Rake - how do I copy a directory of assets to RAILS_ROOT + "/public"

I am just getting started with Rake. I am trying to create a rake task
from within a rails plugin to copy some asset files (inside /assets in
my plugin folder) to my rails application /public folder.
How can I achieve this?

I am not sure whether to use FileUtils or File. Where AM I in rake
terms. No matter what I do it keeps saying it can't find the file. Do
I need to use File.join or is there a better rake way? Any resources
out there on how to use rake for file oriented tasks like this? Should
I use a generator instead?