How to replace bottom touch screen that is shattered?

how to diy replace screen, otherwise machine still works just can't use touch screen features with broken screen I dont want to spend alot of money Nintendo wants $80 to repair or replace. It is my 7y son's machine and he broke screen when hitting it when he got overly upset when game was going well. I would appreciate any help anyone can give this single mom. I have made my son wait 6mo to consider repairing it since he did not take the proper care with his game and caused the shattered glass but I thought I could get it working as a xmas gift and give him a second chance to properly care for his game system.