Can I please have some help with the Domain Mapping plugin

I have added a new site to the Salinger Publishing network (multisite). How do I point it to it's own domain, rather than as a subdirectory of Salingerpublishing.com.

Eg. http://salingerpublishing.com/bellavistaweddings/ needs to be just http://www.bellavistaweddings.com/

Thanks,