Hey again. I have a questions about Unity. 

1. What is the difference between textures and materials? Why did I see a video of this weird lady make materials out of textures to use in those "slots" on the right? Why are materials preferred? I tried dragging the materials at the bottom of the screen to the right, but they do not work that way. Is there an automated or easy way of this gun finding all the materials? 

Here on my example I have a gun I loaded in from another project. It has all the textures and materials it needs, but somehow they aren't loaded in. Might be because it's shared to me from someone elses project.

2. I clicked on the Body of the gun. I can drag textures directly into the scene, one by one. Is this the only way to add materials? Some avatars have upwards to 12 materials or more. I've heard it's best to combine those in Blender for performance. I feel like this is a step many skip, hence why so many avatars are bad in performance. 

3. Can you apply material combining to any object or is it just avatars? How do I export a .fbx file easily from a Unity project into Blender? I remember there being an asset dedicated just for that.

4. Should I fix these "missing" textures before I export the gun into Blender for optimization?

5. Is it a good idea to optimize every object separately, then together for the final product? Say if this gun was embedded into an avatar is it a good idea to "clean it up" before or after I've added to the avatar to optimize it? Doesn't optimizing using the CATS plugin reduce quality, so I'd assume it going through it twice really would degrade the quality of the textures?