I think this has probably been answered already, but in case it wasn’t: HTML is what you will create your site with. FTP (file transfer protocol) is how you get the site you created from your personal computer to the DH servers, so the rest of the world can see it.
It is possible to upload your files to DH without an ftp specific software (like CuteFTP). Recent versions of Explorer (I don’t use Netscape, so I’m not sure about that) allow you to do what it sounds like you want.
On your webpanel, go to “Domains” and click on “Manage” on the website to which you want to upload. You will be prompted for your ftp password, which DH provided you when you signed up.