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).
Note: Your sub folder must contain the web banner dimensions (containing an 'x'). For example 200 x 300.
Download this index.html file, (the link will open a new tab displaying the HTML. Right mouse click and select save as...). 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.