I don't use the exact same HTML editor or hosting provider that you do, so this info is more generic then specific. But it applies to most situations.
I use FileZilla as my FTP file transfer program. It's a free program to use to transfer your index.html (that's your temp page file) from your computer to your hosting account.
In FileZilla you'll need to know the primary domain name your hosting account is using, you'll need your user ID and password (this should be your user id and password for your cpanel login). With this info you should be able to connect to your primary domain and any other secondary domains in the account. I'm assuming you have a standard shared hosting account.
Once you're connected to the hosting account, all of your secondary domains that you have should be listed under the directory called public html (or similar). Then just upload your index.html file into the root folder right under the domain.com folder that you are working on.
This sounds a little confusing but it's much easier than I've made it sound.