Management team members usually lead their own team, who help to implement the strategy of their leader into action. Within each team there would be different functional roles, which with growing organization often trigger further deepening of the levels of the corporate structure.
As the rising entrepreneur, you would probably be combining managerial and operational responsibilities as well as merging different functional roles. You would be your own marketer, accountant and web developer. At least until the time you build a solid prototype and approach the investors. If that’s not what you are planning, a way to reduce costs would be to try finding volunteers to help you run the company or gather enough co-founders with diverse skills and dedication, who would be willing to put work in without getting financial returns in the immediate future.