I just bought Galactic Civ endless universe

As mentioned in the topic title, I am new to turn based games and am getting used to this type.

My first question is:

Do I wait for the "turn" button to turn green before I click on it or just click away?

Also, Is there a guide book other than the one suppilied with the disk?

I have looked at the tutorial on this site and it has helped greatly

I will try and search for answers to my questions but some of them may be so simple that people may not have asked.