Ann, assuming you simply wish to put your domain online you need to obtain hosting. The place you registered your domain may offer this, or you could use any number of hosting services (I have used webhostingworld.net and hostgator.com)

Simply upload your site where your host tells you to. If your hosting is provided by your registrar it should just work, if you are using a different host you simply need to change the nameservers of your domain (this is a simple task and the details will be provided by your host)