This tutorial shows you, what you need to do to start using GLA animations in your Unity game
Assets -> Import Package -> Custom Package… and select GLAPluginPackage.unitypackage
Keep all checkboxes selected and click Import
Now you have all you need to start using GLA in your project.
Now you can import your first GLA Animation. Go to folder with your GLA animation and drop the .gla file anywhere in the assets window in the Unity editor. You should see GLA Asset with name of your animation and GLARawData directory. Do not modify this directory.
Grab GLA Asset and drop it into scene. You should see animation’s first frame like the one displayed on the screenshot.
Congrats! Now you know how to add GLA animations to your game.