What this guide covers: LITS Settings' two tabs, and why you'd set these up before registering animals.
SpeciesSpecies
Found at LITS → Settings, the Species tab — a name and a code per species. Some species may already be seeded for you; add your own with New Species.
BreedsBreeds
The Breeds tab links a breed's name and code to one of your species. Registering the species and breeds you actually keep here first means the Animals page's Create Animal dialog and its filters have something meaningful to pick from.