In the sidebar menu, click on Products.
​
Then, click on the Edit next to the product you want to replace a file for.
​

Find the file or lesson that contains the file you want to replace and click directly on its name.
​

Click directly on the uploader to replace your file. You can choose to upload a new file from your computer, choose a file from the media library or completely remove the file.
​

Once you're done selecting your file, click Save in the lower right-hand corner!