Resolved Material Makes Gameobject Transparent... Not what I want!

Hello, and thanks for taking the time to read this. I am following a simple tutorial for a hexmap, as I want to utilize/learn how hexmapping can be used and how it works. I imported a model from blender from said youtube tutorial (a simple transparent hex). However, whenever assigning a material (I am just dragging it on. Opaque, Green. Default Shader), the hex goes transparent, and is unclickable in scene view. In my searches on google, I suspect this has something to do with a UV map, but I am not sure. Does anyone know what issue I am facing? If it is a UV map, Can someone explain how and what a UV map is?

Here are some pictures:

Hex Model in Inspector: (This model has an empty gameobject as a parent.)



Material in Inspector:

 

Is it completely transparent? Probably flipped faces.

 

@kdgalla it was, but I already fixed that once I realized that. However, now it takes the material and makes it significantly darker. Green is just black. Light green, is REALLY dark green.

 

I just forgot to use unlit shader...

 

You can use a lit shader too. You just need to have enough light, in that case.