Getting files to keynote

I have a file on my wifi flash drive. It’s actually a PPT file. How can I open and edit it in Keynote on my IPAD? I can’t seem to be able to get it there…

Currently “open in” another app is not supported in the sandisk WFD app. All you can do is preview the ppt. 

Other users have reported the Airstash+ app also words with the WFD and open is is supported in the Airstash+ app.

That can be opened by a PowerPoint by default. On your Ipad, what software is installed there that is similar to a PowerPoint?