For your own security, TenX strongly recommends that users do not install the app directly from an APK taken from a non-Playstore source.
Furthermore, the app uses some Google Playstore services. Without ready access to the Google Playstore, your experience may be severely impaired.
You will need to somehow find a way to access the Google Playstore to download the app. We do not have any other way for you to access the app at this time.