For y'all people having trouble with dev options and USB debugging to install apps, put an apk from your computer into the downloads folder on your phone. Now put other files in the downloads folder. Select a non apk file and click move. When in the "move" mode, you will see that the apk has an application icon on the front of it. All I'm saying is that the system detects apk files as applications. I will post a video later on how to this.