You can install DFNDR simply follow the following steps:
Open the Android app store on your phone by selecting the Play Store icon.
Touch on the search bar at the top of the store.
When you open the search bar, type: DFNDR and select the DFNDR - Privacy & Boost.
After reading the required permissions, touch "Accept".
Wait for the download to complete.
Congratulations, DFNDR has been successfully installed! Open and protect your device.