Instructions:
1. Place I2_Robin the chosen version into any DLC folder i.e. "D:\SteamLibrary\steamapps\common\Batman Arkham Knight\DLC\313100\"

2. Simply press play if you don't want to customize anything : )

Optional:
To remove any skin remove a line in it's entirety as shown below:

https://imgur.com/Yzm6331

If you want to reorder the suit simply change the sort index to the order you want in game:
Nightwing Sort Index 3xx (ie. 372, 373)
Robin Sort Index 2xx (ie. 272, 273)