I have a structure like this:
ACME
-- ACME East
------ Mark Jones
ACME and ACME East are companies, Mark is a contact at ACME East.
I read at \https://www.odoo.com/forum/help-1/question/multi-level-customer-structure-how-can-i-add-a-subsidiary-to-a-company-record-not-a-contact-i-need-a-grandparent-parent-child-hierarchy-for-my-customer-record-122659 that this structure is supported.
How can I structure my Excel/CSV import files so that I can import thousands of contact and company records?