In each turn, you must go to the R+D center to create and answer questions. In the R+D center you will be able to create, answer, and debate the questions that have been created by the rest of the players. These are the three possible ways to obtain GCoins.
With GCoins you can construct and evolve the buildings in your map. You can create new buildings, evolve those that you have already constructed, and demolish the terrain to continue constructing.