Currently, files cannot be uploaded to your Ning Network server via FTP or WebDav, unless you own an older Ning Network and still have access. In other words, you cannot upload files to a server and folder structure in the traditional manner.

Why Would You Need to Upload a File?
There are several Ning hacks, and tutorials showing you how to implement the hacks. In a lot of cases, there is a need to upload a customized HTML file.

The example will show you how to upload an HTML file, since most Network Creators know how to upload an image.

How To Upload Your HTML File to Ning Servers:
1. After you created your HTML file, and saved the file - - be sure to know where you saved the file on your hard drive. For example, you may have saved to My Documents. You must know this when you upload the file.
2. Add a Blog on your Ning Network.
3. From the Rich Text Tab or Canvas Area, click on the "Attach File" button. It is located to the right of the "Insert Image" button.
4. Browse and find your HTML file on your hard drive, and ADD the file.
5. After the file is added to the blog, click on the HTML tab. Copy the file name path starting after <a href=" all the way through the .html

The point is: you need to know the file path of the HTML file, so you can tell your Ning Network where the file is located, when you need to "call" a customized HTML file into a Ning hack.

Here's a good example of a Ning hack and tutorial, where you will need to know the file path of an uploaded file:
How To Add Google Ads to Header