you have imported the site into FrontPage on your machine?
Once you've done that, the best thing is ti save it to your hard drive (the local copy). The do your alterations and publish the site back to the server from within FrontPage. That will overwrite the server version of the site (the remote copy) and your alterations will be visible.
The advantage of saving the original version of the site to your machine is obvious - if things go badly wrong you still have the original site as a backup.
Once you have sussessfully published your changes, and are happy that all is well you can save the changed version to your machine - now you have synchronised versions, and can make changes at any time, using the same methodology. It's bad practice to work live, on the server version at any time - at least unless and until you are very comfortable with the way FP works.