Chosen Solution

have cracked glass digitizer how do I replace it

The Nokia Lumia 1520 display is glued to the digitizer and glass. i find an video on youtube. hope this help you , https://www.youtube.com/watch?v=sIVJxqfW

This video is with a man speaking when replacing the display. https://youtu.be/WkGfydis6ZE

Replacing the glass is nearly impossible without specialized tools. I highly suggest you just buy a new LCD/Digitizer already assembled.