2021-8-15 · The simplest form of process flow diagram is linear. The key steps in the process are identified, laid out step by step, and subsequently verified by the HACCP team. The diagram shows a simple 8-step process, where one step follows the next in order: Step 1: Purchase. Step 2: Receipt/Storage. Step 3: Preparation. Step 4: Mixing. Step 5: Cooking.