These are Giants full range of added layers from both maps, combined into one entry for your map making experience, this allows you to take full control of the paintable textures that Giants have already gave, into 1 map edit and create the look you require.
These are easy to place if you have the knowledge of editing i3d and the use of Notepad++
But there is a useful README file within the zip, that explains everything from the start to finish, and getting these paintable layers into your i3d file. Please take note of the readme file and follow it step by step, otherwise making a simple mistake could stop your map from loading in GE, so take particular attention to entering these needed files.
ALSO can't say this enough! PLEASE MAKE A BACKUP before attempting this addition.
All is left to say Enjoy and have fun mapping.