Search Page …

I’m looking to change the existing (default) Search results but don’t know where to begin.
What I’d like is a page that displays a “Search Results” image at the top followed by the applicable post title(s) and a little excerpt from the applicable post(s) that the search word was found in (rather than the whole post).
I was also wondering if someone might be able to help me with the “No posts matched your criteria” PHP. I’d like to be able to have it display like so:
“Your search for “$searchvar_here” yielded no matches. Please try again”.
My PHP coding skills are pretty much non-existent but if anyone can suggest how I might get started on this that would be great.
Cheers and Thanks!