Frontpage can be used as a regular FTP client, but be aware that built‑in Frontpage features such as counters, forms and the like do not work with FTP upload.
Choose Files -> Publish Web Site

Enter your domain name under the Location field and in the FTP folder type: public_html – your web content must be placed in this folder to be displayed on your website.

Enter username and password and click OK.

When you can edit your site again, Frontpage has finished uploading.
Article from the support category: FTP