Hmmm... Amazon won't do any promoting for you, aside from putting your book on various Free Book Bestseller categories if you give away enough to qualify. There are a lot of excellent threads on the Writer's Cafe about how to have a successful free run, but for me, it comes down to having an attractive cover in a popular genre with a good blurb. If you have those things and alert the sites that highlight freebies, you can have a great free run, assuming the sites pick you up to promote. The most popular sites require certain numbers of reviews and a certain level of star-ranking in order to promote you.
The Author's Marketing Club is a good place to start. You have to register there, but it's free. They'll have a good starting list of places you can alert about your free book. It's not all-inclusive, but it's a good start.
When I did my first run, I found this very helpful, written by a KB'er:
http://ruthnestvold.wordpress.com/2012/03/04/promoting-ebooks-with-kdp-select/
Here is the long-running thread that where people on the Writer's Cafe have told about their own experiences with free runs. It's very long, and things have changed since it was started, so you might want to go the the very end and then back up about 20 pages or so:
http://www.kboards.com/index.php/topic,98775.0.html
After that, if you have some more specific questions, come back here and post them and someone will probably come along and answer them.
