Connections Entity List: Account Field

Using the Connections entity, I want to create a list with related Accounts and their respective roles to Opportunities. I want to place this List on the Opportunity form. So, if I use the connections entity i will get the role as part of the columns but I will not be able to add any record to that list using a Plus button. How can I add a Plus button? and most importantly, How do I differentiate between Acounts and for example Stakeholders on the fields found in the Connections entity so that I know which column to choose on the List?