I'm trying to understand how certain contacts should be configured and how CSV files should be set up to correctly import them in. Customers for starters; they are based on whether they have an invoice or if customer_rank is set to 1. That customer can be a company or an individual, easy enough. If its a company and that company has contact information you want to add into it, then we have fields like Related Company(parent_id) and company_name which is what it gives you in the customer helper template that you can download. There is also the field buyer_id, which I'm not sure if that gets populated after sales orders or if it should be set as the customer/company, customer/company/contact, or what. The field address_type has me wondering as well.
So, when to use parent_id and company_name, and how does buyer_id work?