1. OpenIV 
2. Go to GTA V/x64e/models/cdimages/streamedpeds_ig/ig_amandatownley 
3. Back up any files that you are replacing 
4. Click edit mode and click yes 
5. Replace (click + icon) the all 4 .ydd and .ytd files

personally recoment to use Enhanced Native Trainer to spawn and modify characters.

Thats it. Your done.! 