This plan will be created upon plugin activation. This is a must have plan you can't delete this plan. Any restriction regarding to this plan will be applicable to the non registered user and user without any subscription.
So before creating any new plans, you first have to fix the restriction for this default plan. You can set any plan to default. If you set your plan to this default then This plan is non paid plan. You can edit any restriction for this plan to your need.
Details about how you can configure default plan restriction will be discussed in restriction sections.