Guys,
I am having a lighting issue I guess. I have created new 3 meshes and put them into the scene. I placed 3 point lights either. While editing the scene everything’s gone well. I was able to see the base colors of the meshes and the scene was lighted. However, it became all dark when I build the scene or pressed play. What is the problem?
I do not think so. Actually, I do not know. I have created those meshes with blender with no extra configuration. I have no experience in 3D modeling. If you guide me how to find if it has or not, I can give more concrete info.
Detailed Shape Info Below:
Maybe you can follow this tutorial : https://www.youtube/watchFmaDwlNBTU
Or google something like : create Uv Lightmap blender
Ok so what I have to do is that I should get rid of that UV Lightmap right?
Ok then. I will give it a shot 
and inform you guys as soon as possible.
Do those meshes have unique lightmap UV’s?
No, you NEED a lightmap UV with no overlapping faces for your mesh so that you can build lights properly. So follow the video Dusaral provided.
Also take a look at this website to get more information about lightmaps: Here is another lightmap tutorial for blender:
It solved my problem. Thanks a lot guys!
Now I gotta understand what this lightmaping is all about
I have solved my problem with the second link.