1. In order to do these open settings.
2. Find and select security.
3. Check unknown sources.
4. Confirm it.
5. You can now install apps from unknown sources! Congrats!
The best unofficial site about Android. By viewing this site you agree to the ToU available here - http://bit.ly/2NB9Ngc
Download the rom HEREThe rom is based on kitkat 4.4.4. I scanned it with many antivirus engines and none detetcted viruses in it.