With a business model, you describe the rationale for how your organization creates and delivers value to customers; and how in turn it captures value for itself.
The business model communicates the logic driving the value proposition for the customer from your organization; specifically where revenues are coming from, what the costs are, what assets and partnerships are utilized. It is how the organization makes money and hopefully a profit.
When designing business models, start with the question, what is it that the customer needs to get done, and how do we help. This question is central to figuring what is the value that the customer places on your product or service. Having a deep understanding of the customers, what they hope to accomplish, and how well you can meet is at the heart of a business model.