Starting a business (a gym)

I will open my own gym in October. The thing that I’m worried about is how can I manage the money and what if I couldn’t pay the coaches. I’ll have 4 at the beginning. How I’ll will do the marketing? Do I need more than one secretary? I have all the mixed feelings anxiety, stress, excitement, and can’t wait to it to start. I want to organize my feelings and my thoughts. I want to know how to think as business owner. I feel more organized putting priorities and focus on them.