New to Modding

Hey everyone, first of all I am so glad this site is still around (so many others have closed!)

I am new to modding The Movies (but have modded other games) so please bear with me if these questions are stupid or have been asked/solved before. First of all, I am using Dragon UnPACKer to view and unpack the .pak files, but when I extract the "meshes/extrainfo" files and open them with Notepad++, the .inf files are garbled nonsense (just symbols and random snippets of text - is this normal or am I doing something wrong? I have tried using MED to extract them instead to see if that made a difference, but I get the exact same thing. I am also curious - in some some of the files it mentions a "/movies/Dev/Build" folder -- where is that?

What I would like to do is alter the meshes of the in-game facilities and sets so that their bounding boxes (the yellow box surrounding an object when you place it in-game) aren't stupid weird shapes - I would like to edit them to be square and tighter to the actual object or make them overlap. I have viewed some of the meshes with Blender, and I don't see parameters for bounding boxes or placement in the mesh files themselves, so I thought that information might be in the corresponding .inf files and coded in but again, I am not really sure what I'm doing as I'm new to modding this game.

Any help would be super appreciated!!! Thanks