Replace desert textures with grass

[Masa]

Like the title says, how do I do that? I've already got the .txd files.

[Castillo]

engineImportTXD 
engineLoadTXD 

[Masa]

Do I need to add the ID?

[Castillo]

The object model, yes.

[IIYAMA]

Or take a look at this shader, you replace textures(stone/sand/grass, etc.) which count for all objects.