The first step to creating a business continuity plan is understanding what business processes you need to be worried about. Critical business processes are those that are necessary for the survival of the company due to—for example—loss of revenue, customer service interruption or brand damage (just to name a few). Ask yourself: What business processes are absolutely crucial to keeping your company running in order to avoid a severe negative impact?
If you’re a manufacturing company, any business processes that make you unable to continue producing an important share of your product portfolio should be labeled as critical business processes. Identify what these are, and then describe the exact process, including the location where it occurs and who the parties involved are. For example: If you require a specific type of raw material to keep your production line going, detail the processes involved in making sure that material gets to your plant.
My pro tip for this step (and all of the steps): Make sure you're involving the relevant people in your business continuity planning. Business continuity is a joint effort, and must be understood by everyone who is part of maintaining it!