1 - Extract the files from the .zip

2 - Copy the extracted folder with its files into your Blender Asset Library path if you have one. If not you can create a folder called BlenderLibrary somewhere into your computer then copy the Simple Swarm Library folder there and in blender you can add it by going to Edit

3 - Done you now should have all the swarm presets in your asset library.

- To use custom creatures you have to add it to a new collection and give it the appropriate name. Also you should only add the mesh to the collection otherwhise the bones will show in the swarm aswell. 

- To make animations repeat more time go to the Nonlinear Animation Tab and press the "Push Down Action" button. Then press "N" to make the right menu appear and scroll down to Action Clip