Hello,
First of all, you need a webhost. As you can see, there are free and paid ones. Depending on your needs, you will have to choose which you go for. If it is a business site, paid would probably better because of uptime guarantees.
If it's just to test some code etc, a free host would be great. When you choose/contact a host, they will assist you in getting your site on the net. This is most of the time done via FTP.
You also need a domain, again, depending on your needs, you could get away without one. Some hosts will give you a subdomain, which means you will have for example, yoursite.yourhost.com.
Need more help?
Just ask, we're here to help.
Regards,
Matt Midgley