Little confused about how to even install the thing, I've implemented addons and plugins in the past and nothing seems to work

Sorry if this is a stupid question I just have been stumped! Thanks for the help! 

To properly install Baby 3D with all its parts you should unzip the archive you downloaded. Then open Construct 2 and drag each file with a c2addon extension into the C2 window. This will prompt you to install the addons.

Every behavior and plugin you use depends on the main plugin ("baby3d") which needs to be present in your project.