You can use the following two methods to Reset your Billion Capture Plus:
Tap the Settings icon on your home screen or app drawer.
Swipe up to scroll down to the bottom of the settings menu.
Tap Backup & reset.
Tap Factory data reset. Tap Reset phone.
Tap Erase everything.
Switch off the phone.
Press and hold volume up and power button till you see a menu.
Select Wipe all data and cache.
Confirm and you are done.
You can check the full specs here: Billion Capture Plus
To set an MP3 file for use as custom ringtone system-wide, do the following:
1.Copy the MP3 files to your phone.
2.Go to Settings > Sound > Device ringtone.
3.Tap the Add button to launch the media manager app.
4.You will see a list of music files stored on your phone.
5.Your selected MP3 track will now be your custom ringtone.
You can check the complete specs of this phone: Billion Capture Plus
The Billion Capture Plus comes with a fingerprint scanner on its front that can be used for quickly unlocking the device.But to hide or protect your apps I would suggest you use App lock.Heres how.
Now, whenever you open a locked application, you can either unlock it by simply verifying your fingerprint or by entering the unlock pattern. The fingerprints that you have registered for unlocking your device are the ones that will also work with App Lock.