We have a full ‘getting started’ walkthrough video here, which this video has been taken from. The getting started video will walk you through the basics of your account such as creating products and funnels.
Your ‘main’ product starts as the base for your funnels. It’s the primary product that your bump and upsells/downsells are connected it.
It’s the product and page where your customers enter all their details and payment information.