How to properly export into .obj and .mtl file I'm writing a very simple program in OpenGL, and thus I'm not a blender expert.

I found  nice 3d model here : http://tf3dm.com/3d-model/crysis-2-nanosuit-2-97837.html
and I'd like to export it as .obj  file with proper .mtl mapping (map_Kd, map_Bump,  map_Ks)

So I want it to be looking somehow like this .mtl file http://learnopengl.com/data/models/nanosuit.rar

The second link is taken from the tutorial, where the Tutorial-Writer already made some exporting but hadn't tell what kind of (how to do it).

Thank you in advance for help, links and all the advice :)
Are you having trouble exporting in general, or exporting that specific material?

In general with Blender, the .mtl export settings are in the .obj exporter. Check the Write Materials box to have Blender generate an .mtl with your .obj.