First open your FileZilla, and login to your account.

Next, open notepad. Type out your page that you want to add to your domain, for example if you would like to add a graphics page name it "graphics.php / graphics.html" (i recommend you use php files, it's easier for php includes.)

After you name it, click "All Files" under where you named it, then press save.

Finally, go back to Filezilla. On the right side, find your file and drag it over into the left side, and there you go, a new page on your site :)