Site Search Function

So Google are genius at searching, just not genius when it comes to telling you just what you need to do to implement a search function on the site.
I think i figured what to do, So far i have registered the site with my Google account and included this piece of code they ask you to put in just to verify you're with them. I then uploaded my sitemap to the custom search and i'm just waiting to the pages to be crawled to see if it works.
Fingers crossed!