What I have to do if I want use just a part of Urho3D source code, not whole?
For example, if I want to use only Urho3D containers, can I put only Urho’s “Container” folder in “external” folder of my project’s source code directory instead of putting whole Urho3D source code (i.e whole “Engine” folder) into it?
Sounds perfectly doable, just don’t expect especial support for it. You may have to do some adjustments on your own, for example the Container folder files have “#include <Urho3D/Urho3D.h>”. Finally, remember to comply with the license just as if you were using the whole engine.
To comply with the license I thinkI have nothing to do if I don’t modify the files is not it?
I mean just having the Urho license text somewhere. Well, practically the code files already have it. 
Thanks for you answer!