Generate a full detail guide explaining key business metrics (KPIs) for non-financial founders. The guide must simplify complex metrics. It should include clear definitions, the formula for calculation, and why each is important for: 1. Customer Acquisition Cost (CAC). 2. Customer Lifetime Value (LTV). 3. Monthly Recurring Revenue (MRR). 4. Churn Rate. 5. A section on how these metrics work together to tell a story about the business's health. Please include a disclaimer to consult with a financial advisor.