How can you make a real time strategy game with c plus plus

You don't. You hire a team of programmers and designers who have the skills and manpower required to develop real-time strategy games. You could use off-the-shelf game engines to model your game, but you would be tied to the constraints of the engine. However, that may be enough to demonstrate your concept and perhaps gain the necessary funding to hire a team of specialists. Alternatively, you may be able to sell your concept to a 3rd party games developer.