Use APKPure App
Get SeriesGuide Extension for Plex old version APK for Android
Find your video in SeriesGuide and open it in Plex.
This is an extension for SeriesGuide and Plex applications. It cannot be used without these.
Settings screen is added to help users to install SeriesGuide and Plex.
If you already have them, you remove the Settings screen from your homescreen and app drawer as well.
Enjoy.
The app is open source here:
https://github.com/tasomaniac/SeriesGuideToPlex