I think there is an mSATA connection that you will have to complete dissemble your Notebook to get too. I also think with out modification only a 1/2 card length will fit.
Search these threads, several people have accomplished this. "Install, mSATA, drive G46" this bring up 25 or so threads on this MOD.
Also search the
http://forum.notebookreview.com/asus-gaming-notebook-forum/ several people on there have discussed this MOD.
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