The functioning of any organisation is something like breathing. Breath in, breath out.
The first breath in is the injection of cash and human resources. You need some money and the people (even if only you) to set up and start the company and do the work. Then the out breath, you outflow, start promoting and getting yourself known.
Then breathe in and start attracting customers or clients. Sales is actually an inflow, even though this is normally considered an outflow. You are bringing in people, bringing in, pulling in interest in your products or services, drawing people in.
Now for the next our breath through production and delivery of your products or services. With success in this area we get the next in breath, income, money starts coming in and so we can start again and let the cycle repeat. In essence that is all there is to it. Breath in and breath out.
Resource, promote, produce, receive and repeat.