UMS Enabler (Universal) APP
The correct procedure for using UMS Enabler is the following: first you connect the Android device to a PC or a TV, and then you open the app and press the button to activate UMS mode. That's it. With just these two steps, you can activate UMS mode.
It's important to note, in order to use UMS Enable, you're Android needs to be rooted. Without root privileges, the app won't work correctly and actually, you shouldn't even install it.