Complete Reference for D&D

Update: I emailed the files to myself like read about Someone else doing, and opening the file in the email worked for importing

Hey, I am having trouble importing to the 3.5 app, all the files are .dd35, the app has the permissions needed, but with my phones built in file browser and astro, it says no app can open this file.
I have a Samsung galaxy s8, Android version 7.0.
I think it may be a compatability issue with android ...