Create a master folder to house all your sub folders.
Inside the master folder, have one folder for each of your web banners (each of these folders should contain the HTML and imagery for the banner).
Tip: Name each sub folder with the web banner dimensions.
Download this index.html file, then add this index.html file into the master folder.
Zip the master folder, then drag and drop the zipped folder onto the dashboard file dropper to make an HTML proof.