First of all, I want you to transfer an existing app on Window server to php server. On top of that, please make a slight change for mp4 files to be played on my app.
This app allows users to install educational apps without wifi connection.I have downloaded all these apps that I think are good for most users from www.apkpure.com. I then upload them to my server so that users can also download them from my app OR server. On the other hand, I transfer these apk files to a folder called GENIUSLINK, my app will then link to this folder and allow the installation without going online. It also works like SEARCH EVERYTHING app, when users click to install an app or play a video with certain names on my app, it'll link to the files and folders kept in the SD card and trigger the installation.
Please view this Youtube video for further information : https://www.youtube.com/watch?v=xpqoqa9PwNc&t=36s