It's actually really straightforward!
Here, check it out this example:
[OBJECT:GRAPHICS]
[TILE_PAGE:CRITTER] This is what you are calling the page
[FILE:critters.png] This is the name of the image file from which you're pulling sprites
[TILE_DIM:18:18] This is the size of each sprite (width:height)
[PAGE_DIM:40:20] This is the number of sprites on the page
[CREATURE_GRAPHICS:CAT] This has to be the same as the creature tag in the RAWs
[DEFAULT:CRITTER:0:0:AS_IS:DEFAULT] (CRITTER is the name of the page)
(0:0 is the location on the page; here, top-left),
(AS_IS just means you don't want the game to do any coloring for you)
[CHILD:CRITTER:1:0:AS_IS:DEFAULT] Kitten
[ZOMBIE:CRITTER:2:0:AS_IS:ZOMBIE] and undead
[SKELETON:CRITTER:3:0:AS_IS:SKELETON]
[CREATURE_GRAPHICS:DOG]
[DEFAULT:CRITTER:0:1:AS_IS:DEFAULT]
[CHILD:CRITTER:1:1:AS_IS:DEFAULT]
[ZOMBIE:CRITTER:2:1:AS_IS:ZOMBIE]
[SKELETON:CRITTER:3:1:AS_IS:SKELETON]
[TRAINED_HUNTER:ANIMAL:0:2:AS_IS:DEFAULT]
[TRAINED_WAR:ANIMAL:1:2:AS_IS:DEFAULT]
etc.
Professions are the same deal,
but it's all under the same definition:
[CREATURE_GRAPHICS:DWARF]
[STANDARD:DWARVES:0:0:AS_IS:DEFAULT]
[DEFAULT:DWARVES:0:0:ADD_COLOR:DEFAULT]
[CHILD:DWARVES:1:0:AS_IS:DEFAULT]
[BABY:DWARVES:2:0:AS_IS:DEFAULT]
[SLAVE:DWARVES:3:0:AS_IS:DEFAULT]
...
etc.
More on-track:

Moo.
I think she's a little too grey, maybe.
I might make her more like the color of the horse.