the full url of your web site. For instance, if you were going to publish changes to this site you would enter this:
http: // www. pcadvisor .co.uk
(I've inserted spaces to stop the site code from creating a 'click here' hyperlink)
Click on the button to publish, and wait for a few seconds - provided your web space has had the FrontPage extensions installed by your hosting company the server will issue an authentication challenge, and you should enter the username and password provided by your web host into the little box.
That's all you need to do - FrontPage will then upload all the necessary files to the server automatically.
make sure to save a copy of the site to your hard drive - don't just rely on the server copy. Then, when you want to alter the site, or add things you should open the copy that's on your hard drive. Make the alterations/additions and then publish to the server. That way you'll always have two identical copies - one on the server and one on your computer. Don't be tempted to work on the server copy directly - if you do, you'll run the risk of getting the two copies out of sync, and the next time you publish from your hard drive you'll overwrite all your previous work.
I hope I haven't complicated things by saying that.