How can I download the apps?

You may download the apps using following URLs:

iOS:

https://apps.apple.com/app/id1546216363?l=en

Android:

https://play.google.com/store/apps/details?id=smartech.online.taqreeb.sunnah&hl=en

What is the reference of the hadiths?

Jame` al-Osoul, Ma`alim al-Sunnah, and al-Wajeez