Put the folders inside "More Starbound CrittersNScenery (drag mods out)" into Starbound's "mods" folder.

Each folder is a mod that does something different:

!0_More FrackinUniverse Critters!	- Use if you have FrackinUniverse installed. Note: must have More Starbound Critters installed in order to function.
More Starbound Critters		- Main mod, adds new critters to vanilla biomes.
More Starbound Scenery		- Secondary mod, adds new scenery objects to vanilla biomes.
Passive Monsters	- Adds passive generated monsters back into the game.
Peaceful Monsters	- Unique Monsters now spawn as nonaggressive.
Vanilla Critter Cages	- Makes vanilla critters catchable. Don't use if you're using a mod like "YourStarboundCrew" which also makes critters catchable.