On your AppScenic Account, go to Import Products, then Online Feeds.

Now find the feed/file you want to clone or duplicate. 

Click on the Actions button on the other side of that file. 

Choose Duplicate and then confirm your choice on the pop-up window. 

And you are all set! 

Now you only need to edit or update your feed by following the same steps like the ones for creating a New Feed. 

If you don't remember how to do that, check these steps here.

And this is how you duplicate an online feed.