I have the pdf reader app and I'm able to see all my .pdf files within the app's own library. Every time I go to open one of the files, I get a prompt about viewing the file in MS Edge instead, as support for the pdf reader app will be discontinued. However, I don't know how to actually open the files with Edge, and I'm also unable to locate the files using Files Explorer. I can ONLY see my pdf files within the library of the pdf reader app itself. What to do?? I'm using WP 10 mobile on my Lumia 950 XL.