Well if you have seen all the Video's of how to dissemble G75 just stop at the point you remove the keyboard, put in your new one and reassemble.
Maybe you missed this one good luck my friend.
G752VY-DH72 Win 10 Pro
512 GB M.2 Samsung 960 Pro
1 TB Samsung 850 pro 2.5 format
980m GTX 4 GB
32GB DDR 4 Standard RAM
Z97 PRO WiFi I7 4790K
Windows 10 Pro
Z97 -A
Windows 10 Pro