As we have said before, the game is based on the official Unity tutorial, TANKS! When we download the project, we are welcomed by a pleasant desert scenario, with rocks, structures, palm trees, and so on. The basic structure of the game is shown in the following screenshot:
It may be helpful to follow the full Unity tutorial, available at https://unity3d.com/learn/tutorials/s/tanks-tutorial. It does not involve AI, but it will teach you a lot of other important stuff for game development, such as how to design a game manager, basic controls, audio, and so on.
The first time you start with an existing project, spend as much time as you can familiarizing yourself with the game structure, the basic scripts, and the components. It is important that you can operate at ease in a project that you don't know. To do this, run the game a couple of times, try small...