1: Checking Textures
Open textures.js
Choose texture (eg. wood = texture_five)
Take texture number (eg. 5)
Minus one (eg. 5-1=4)
There's your texture Id
2a: Custom Textures Method 1
Open textures.js
Pick which texture to change. (eg. Grass)
Change its url to whatever you choose (eg. "Textures/Grass.png" to "example.com/Grass.png")
2b: Custom Textures Method 2
Open "Textures" folder
Edit any texture you want.
0 - Grass
1 - Water (lvl1)
2 - Water (lvl2)
3 - Ice
4 - Wood