I want to start distributing downloads from my supplier and I need to
[color=#404040][font=tahoma, arial, verdana][size=3]Set up an empty page on your website and insert the following line of code into the content area of your website:[/size][/font][/color]
That iframe creates a login form, presumably when you log in it takes you to the downloads page.
You could simply add that iframe code to a Page via Website>Content. Click the HTML icon on the Content and paste the HTML code directly into the html editor.